Natural Selections

The Tree of (a Secret) Life

by janem on March 23, 2017

story and photos by John Ernst

As it stood in February of 2016.

As it stood in February of 2016.

One summer during college, I worked as a landscaper at Genesee Valley Park. I savored the chance to work outside. Each day I would drive my Gator through the misty sunrise at 5 a.m., surveying the park and ensuring that all was well before hikers and picnickers arrived. And each day, I marveled at the mighty branches lying on either side of the trail. It was a bitch to mow and weed whack, so other employees let the grass grow, giving it a wild and unkempt appearance. A few weeks into my job I learned it was called the “tree of life,” and that it had been struck by lightning, breaking it in half, years before. Feeling an odd sense of connection with the tree, I started taking better care of it.

Years later, my attempt at research on the tree has borne little fruit. Its only online remembrance seem to be a photo gallery on the University of Rochester’s website commemorating the tree’s life, and a memorial page on Facebook. I learned that it was struck by lightning on July 4, 2010 and before it fell, it looked like a pair of hands opening to the sky. I also learned how genuinely Rochesterians loved it. Both the photo gallery and memorial page highlighted that.

For more information I called the Monroe County Parks office, which referred me to Chris Kirchmaier, Supervisor at Highland Park. He told me that he was actually on the forestry crew that cut down the tree the day after it was struck. “I’m not sure that there is a recorded history,” he said, “just a popular tree and a cool structure. Every day I drove by there were four, five, even ten people sitting in it or climbing it.” He told me that he’s only 36, and that his older co-worker Joe Bernal, the tree crew supervisor, might have more answers for me.

“Well, it’s a white oak,” Bernal told me when I asked what he knew about the tree. “It had a perfect crotch, probably eight or ten feet up in the air.” Frederick Law Olmsted designed Genesee Valley Park in the late nineteenth century, and Bernal figured the Tree of Life predated that. “That would make it over 150 years old, and that wouldn’t surprise me,” he said. Earlier in his career, Bernal removed tags from the trees Olmsted had planted, but didn’t remember the Tree of Life having one. He expressed similar fondness as Kirchmaier had for the fallen tree. “Even when it was busted in half, I tried to keep the character in both sides and moved it down to the path.” He said that he’d like to see the tree preserved: “White oak is a wood that lasts,” he said. “But if we really wanted it to last, we’d have to lift it off the ground, get the bark off, and maybe coat it with some preservative.” As Supervisor, Bernal doesn’t have the time to take on a project like that, but hopes somebody does—perhaps a group of volunteers or students from the U of R. “It’s something I’ve always wanted to do,” he said before signing off.

Tree rings

Tree rings

I decided to revisit the tree and count the rings myself. I had forgotten how huge it was; heaving it up and preserving it would be no minor task. I set to counting the rings on the stub of a lopped branch. Many were so close together that they were indistinguishable, and the cracks didn’t make it any easier to count. I deemed it impossible to record any sound empirical data using this method, but I counted over a hundred rings. Maybe Genesee Valley Park’s ancient oak has no recountable history, but the Tree of Life has earned its nickname.

 

John Ernst is a passionate writer, hiker, and video gamer born and raised in Rochester. He is currently developing his website, nerdofearth.com.

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by Michelle Sutton

The timing of fall foliage color emergence is a phenophase that citizen scientists can track for Nature’s Notebook.

Gardeners on a Mission

Phenology is a rather clinical-sounding word that describes a passionate field of study. The word comes from the Latin root “pheno,” meaning “to appear” or “to bring to light,” and it refers to the timing of seasonal changes and life cycle events in the natural world. New York Phenology Project (nyphenologyproject.org) Founder and Project Manager Kerissa Battle says, “Gardeners are intuitive phenologists—even if they don’t know it! Skilled gardeners closely track seasonal change—their success in the garden depends on it.”

“Phenophases” are distinct life cycle events; for plants, they include such things as fall color emergence, fruiting, budding, flowering, and leafing out. “When gardeners start seeds, plant, harvest, or collect seeds, they are essentially tracking phenophases in order to grow what they want,” Battle says. “Gardeners also tend to keep records year to year of when things happen in their gardens. This is the essence of tracking phenology—paying close attention to seasonal change and keeping records.”

Across the country, more than 15,000 citizen scientists are tracking phenological data for a proscribed set of plants and animals. Many of them are gardeners collecting data from plants in their own gardens; others are going to designated “phenology trails” and other sites in the community. Many of them are entering their data in an elegant national endeavor utilizing Nature’s Notebook, a data-collecting tool of USA National Phenology Network (usanpn.org).

In 2015, New York Phenology Project (NYPP) observers contributed more than 10% of the national dataset. The national total number of observations recorded in Nature’s Notebook in 2015 was 1.8 million!

Phenology aficionados track “phenophases,” like bloom time of native witch hazel (Hamamelis virginiana). Photo by Michelle Sutton

Phenology aficionados track “phenophases,” like bloom time of native witch hazel (Hamamelis virginiana). Photo by Michelle Sutton

Time of fruitset, like on this winterberry holly (Ilex verticillata), is a phenophase that is tracked by phenologists. Photo by Michelle Sutton

Time of fruitset, like on this winterberry holly (Ilex verticillata), is a phenophase that is tracked by phenologists. Photo by Michelle Sutton

The mission of Nature’s Notebook is to encourage close observation of nature, both for the joy of it and the data that results. Theresa Crimmins is assistant director at USA National Phenology Network. “As climate changes, the timing of these life cycle events also changes for many species. However, not all species are exhibiting changes, and the changes that are occurring are not all in the same direction or of the same magnitude.”

Crimmins says that the implications for this are wide-ranging and not yet completely realized, but include mismatches in the timing of open flowers and the arrival of pollinators, spread of invasive species, and changes in species ranges. “Local observations of phenology can provide critical data for scientists studying the effects of changing climate,” she says.

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About.com Gardening Expert Marie Iannotti participates in phenology data collection for Nature’s Notebook and uses phenology in a variety of practical ways in her home garden. Photo courtesy Marie Iannotti

 

When the Lilac Leaves Unfurl…

One of those data collectors is garden writer, speaker, and photographer Marie Iannotti (gardeningthehudsonvalley.com), whose name may sound familiar because she is the gardening expert for About.com. She has written three books, including The Timber Press Guide to Vegetable Gardening in the Northeast.

Iannotti remembers getting phenology-based planting advice from an older gardener who advised her to “plant your potatoes when you spot the first dandelion.” She says, “I started poking around to see if this kind of advice was just folklore or if there was some research behind it. When I found out the research on phenology is ongoing and anyone could participate in tracking, I jumped in, and I started collecting all the tips that had to do with gardening.”

Iannotti takes part in the New York Phenology Project through Nature’s Notebook. She says, “Tracking phenology is a great way for gardeners to get to know the cycles of nature and which things tend to occur at the same point in time. I started by tracking lilacs and know that when the lilac leaves first start to unfurl, I can plant lettuce and carrots, and when the lilac blooms, it’s safe to plant cucumbers and beans. When the forsythia blooms, I plant peas. It’s not an infallible system, but it’s a great tool for planning and for increasing your knowledge of natural phenomena. And since weather can be so variable, it’s more accurate than counting backwards from your last expected frost date.”

According to Iannotti, phenology makes us more aware of not just the changes, but also when something is wrong. For instance, why would we suddenly be seeing so many grasshoppers, or an increase in poison ivy? When should we be on the alert for Japanese beetles? When will cabbage worms be hatching, so we remember to go looking for them? “I’m also tracking my garden nemesis, the groundhog,” she says.

 

Trails and Sites Near/by You

Kerissa Battle says that one of the great things about the New York Phenology Project (NYPP) is that anyone can create a monitoring site almost anywhere. “Even if you only have space for a container garden outside of your house, or you just tag one red maple on the street in front of your house, or you get permission from the town to mark plants on your favorite local trail—you can join this effort,” she says.

Currently most monitoring sites are situated downstate. Battle would like to see more phenology trails and monitoring sites get established in central and northern New York. “Phenology data has been used mostly to monitor long-term patterns,” she says. “However, if monitoring sites are situated along a gradient—such as north to south or urban to rural—the data collected becomes relevant in the short-term as well.” How does urbanization affect the timing of flowering? Are the same pollinators being seen along an urban-rural gradient? Battle says that an array of monitoring sites that represent all of New York’s diverse ecosystems would allow these types of questions to be addressed.

In addition, central and northern New York are home to some of our State’s finest organizations and academic institutions—many of whom are already well-positioned to set up a site and engage students and the public in citizen science. “Indeed some of the most beloved nature preserves and institutions in New York are already involved—and new monitoring sites pop up every year,” Battle says.

Lime Hollow Nature Center in Cortland recently established a one-mile phenology trail with a focus on five woody plants: red maple (Acer rubrum), sugar maple (A. saccharum), American beech (Fagus grandifolia), witch hazel (Hamamelis virginiana), and eastern red cedar (Juniperus virginiana). They are also tracking the wonderful herbaceous woodland forb, skunk cabbage (Symplocarpus foetidus).

The Finger Lakes Land Trust (FLLT), based in Ithaca, set up a phenology trail in Roy H. Park Preserve in Dryden, where they are monitoring red and sugar maple as well as black cherry (Prunus serotina), Eastern white pine (Pinus strobus), quaking aspen (Populus tremuloides) and Eastern hemlock (Tsuga canadensis). They are looking for more volunteers to get involved with this phenology trail. The FLLT has an intimate history with phenology; one of its founders and its first president was Carl Leopold, son of beloved naturalist and author Aldo Leopold, who was an avid phenology data collector.

According to the FLLT website:

While Aldo is well-known for his phenological observations at his farm and shack in Wisconsin from 1935-1948, the whole family participated in observing nature … those observations have proved extremely important … years later, Aldo’s children Carl and Nina used Aldo’s records to publish a study in 1999 showing that temperature-dependent phenological events are occurring earlier. In 2013, a team of researchers used those same records to publish a new study on record-breaking early flowering in 2012. Just think—the observations you contribute today could lead to an important scientific paper down the road!

Citizen scientists around New York State are collecting phenology data and entering it into Nature’s Notebook. Photo by Kerissa Battle

Citizen scientists around New York State are collecting phenology data and entering it into Nature’s Notebook. Photo by Kerissa Battle

A Bustling Play

Battle set up a phenology trail around her property (which includes her garden) and checks her plants nearly every day when she takes her dogs for a walk. “I get my exercise and slow down my mind while I take in everything I am observing,” she says. “It is meditative and enlivening all at the same time. What could be better?”

“Beyond the pure pleasure of phenology monitoring, you can also craft your garden or yard within the larger context of the surrounding ecosystem,” Battle says. She goes on:

You begin to notice the same pollinators on your tomatoes that you are observing on the milkweed in the field. You begin to notice that the red maples in your yard are flowering later than the red maples in town. You start wondering if the heavy fruit set on the mountain laurel near your garden is because your garden is so lush this year that native pollinators decided to nest nearby and are now pollinating everything in sight. What insects are arriving and when; what birds are hanging around your gardens; what else is in bloom near your garden that might be attracting pollinators?

Suddenly you realize that the pollinators are not just servicing your garden—you are actually feeding them. And then they are moving from your garden to the patch of wild bergamot down the road and the fertilized seeds of the wild bergamot are feeding the birds at the end of the summer, and bam! Your intentional watching has placed your garden in the center of a bustling play—with you as both actor and audience.

 

Battle encourages those who are interested in creating a new NYPP site—which could be in your backyard—to visit nyphenologyproject.org.

 

—Michelle Sutton (michellejudysutton.com) is a horticulturist, writer, and editor.

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Reprint: Trees as Tribute

by cathym on May 26, 2016

Although flowers often go hand in hand with funerals, trees offer a more lasting tribute. What would you rather have, a spray of roses for a week or an awesome oak for a century?

You’ll see trees in arboreta, parks, and other public spaces dedicated to people who have gone before us. Many animal lovers plant a tree as a memorial to a beloved pet. Trees can also mark an important milestone, such as a graduation, wedding, or birth.

My dad planted trees for each of his seven children. He liked variety, so by the time he got to his youngest, I was stuck with a silver maple. Heck, we lived next door to the Highland Park arboretum, so he wasn’t lacking for inspiration. At least my silver maple grew faster than any of the other trees in our yard — giving me something to brag about.

 Shagbark hickory is a slow grower that rewards the patient with centuries of majestic beauty.

Shagbark hickory is a slow grower that rewards the patient with centuries of majestic beauty.

Catalpa delights with white flowers in late spring and brown seedpodsin winter

Catalpa delights with white flowers in late spring and brown seedpodsin winter

I enjoy growing trees with special significance. The catalpa, above, is also known as cigar tree because of its slender brown seedpods. I found the volunteer seedling while visiting the University of Notre Dame, my dad’s alma mater. Groundskeepers eventually would have yanked out the interloper, so I brought it home with me. There’s something really satisfying about saving a doomed plant.

Then there are the two red oaks I discovered growing on my parents’ gravesite. The seedlings were so small I brought them back on the plane in coffee cups. Today they’re 8 feet tall and awaiting a permanent home. (I just need to find a special spot that won’t be disturbed for, oh, 200 years or so.)

Red oak has beautiful fall color and is a relatively fast grower.

Red oak has beautiful fall color and is a relatively fast grower.

Red oak trees are hardy to Zone 3 so Iowa’s cold winters haven’t been a problem for these Upstate transplants. I do have to cut the roots every other year so they don’t get rootbound. I also mulch the pots with leaves for winter insulation. Both of those extra steps will be unnecessary once the trees are planted for good.

By the way, my Rochester-born oaks march to their own drummer. They leaf out later in spring than their Midwestern relatives and take on fall color at their own pace, too. It makes them seem even more special to me.

There’s one other symbolic tree I’d like to tell you about: a black walnut seedling I found growing through the side of a raised bed. I dedicated the tree to a young man who’s experienced some teen growing pains. I’ve shown him pictures of the tree and pointed out that — just like him — it’s no quitter. I’m probably more interested in the tree’s symbolism than he will ever be. But it’s a convenient prop when he can use some encouragement.

Planted too deeply to sprout conventionally, this black walnut forced its way through a seam.

Planted too deeply to sprout conventionally, this black walnut forced its
way through a seam.

That resourceful seedling has an interesting backstory: I brought a nut back with me from the historic Arbor Day Lodge in Nebraska. The nut lingered in my truck bed for weeks — somehow escaping the attention of foraging squirrels — until I got around to wrapping it in chicken wire and burying it in a raised bed for the winter. I soon forgot about it.

Black walnuts can take two years to germinate, so an entire season of vegetable gardening went on above the sleeping walnut. It wasn’t until the second summer that a wiry stem started squeezing through a seam so tight it would give a microbe reason to pause. Talk about the will to live! How can you let a tree with that sort of moxie die? I couldn’t.

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Tenacity alone was reason enough to save the seedling, so it was liberated from its confinement while dormant.

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After feisty squirrels removed the top, the black walnut resprouted into a healthy seedling.

So this spring, when the seedling was dormant, I drilled a couple of holes around the stem to free it from its self-imposed prison. Although the stem was flattened, the roots were in good shape. That turned out to be important because soon after I replanted the tree, a squirrel separated said stem from said roots.

Not to worry; nature has provided black walnut seedlings with the means to resprout in such situations. This time I surrounded the sad-looking remnant with spiny chestnut burrs to discourage varmints if they got through the wire-mesh cage. Talk about killing with kindness: The burrs rested against the broken stem, trapping moisture and causing the replacement bud to become moldy and abort. Could this tree ever catch a break?

Yes, indeed. After moving the burrs back and going easy on the water, a brand new shoot arose like a phoenix from the roots. As you can see, it’s quickly developing into a tree—a special tree with a special significance.

Grow Your Own Tribute Tree
Would you like to grow a tree with special meaning? Search for seeds at the old family homestead, the park where you had your first picnic with your spouse, your alma mater, the hospital where your child or grandchild was born — the possibilities are endless. Many trees ripen seeds in fall, but there are some (such as elms, poplars, and soft maples) on a spring schedule. Oak is a great choice for a tribute tree because it symbolizes strength and can live for centuries. It’s also America’s National Tree. To see the author’s tips on sprouting oaks from acorns, visit www.lowes.com/lci-acorns.

Luke Miller is a native Rochesterian now living in Iowa. Visit his public Facebook page featuring tree photography and inspirational quotes at www.facebook.com/OldsmobileTrees. You can also access archives of his philosophical tree blog at www.lowes.com/reflections.

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Fabulous Native Ferns

by cathym on May 21, 2016

fern,-maidenhair

Maidenhair fern (Adiantum pedatum)

One of the joys of spring is watching ferns unfurl. The fronds start with small fuzzy arcs in the early spring, just poking their little heads above the crown of the plant and slowly growing upward and unfurling like the unwinding of a spring. When I see these fiddleheads, I know spring is really here.

Unfortunately ferns get very little attention as a garden perennial. In most books about perennials, they aren’t even mentioned. This is probably because they don’t have flowers or seeds and somehow people don’t think of them as perennials. They are in fact perennials, reliably returning each year to add beauty, texture and even color to our gardens.

Many people have the misconception that ferns are difficult to grow. This stems from the fact that they seem exotic, tropical, and not appropriate for our cooler climate. That couldn’t be further from the truth. The north east has numerous varieties of native ferns in its woods and meadows. If they grow successfully on their own, how hard can it be to grow a few in our gardens?

Like with any plant, you need to match the conditions in your garden to the requirements of the fern. They are perfect for a moist shady location, but that is not the only suitable habitat. Some can tolerate quite a bit of sun and others will handle dryer soil. All the ferns love leaf mold mulch, which is logical considering in nature they grow in the woods. The important thing is doing your homework before you purchase a fern and find out just what conditions they prefer.

One of the advantages of growing ferns is their almost year round interest. From the spring unfurling, through the summer’s lush textured foliage, to the beautiful caramel and amber colors of the fall, ferns add a depth to the garden that cannot be achieved with the more traditional blossoming perennials whose flowers come and go so quickly. The green provides a resting spot for the eyes as well as making the colors of the blooms around them stand out.

Ferns have been growing for more than 300 million years! In most depictions of dinosaurs there are ferns in the background. In fact, in prehistoric times, they were a dominant part of the vegetation. Today there are about 12,000 species of fern worldwide and more than 50 species native to the Northeast.

The following are some native ferns that will grow well in our area.  Adding native ferns is a good way to contribute to the sustainability of your landscape. The ferns mentioned below are generally available at nurseries and will grow well in our area. One of the most important features of ferns is deer don’t like them! That alone is reason to try a few.

Christmas fern (Polystichum  acrostichoides)

Christmas fern (Polystichum acrostichoides)

Christmas fern (Polystichum acrostichoides): If you want to try just one fern, the Christmas fern has the most adaptable requirements. It prefers rich, moist soil but will also tolerate dry soil. Christmas fern likes shade but will take partial sun if the soil is moist enough. One of the things setting this fern apart is the fronds are evergreen so you have the deep green color all winter. Christmas fern is not invasive. The clump slowly gets larger, staying 12 to 24 in. tall.

Ostrich fern (Matteuccia struthiopteris): This is a large fern, 24 to 72 inches tall and brings a stunning verticality to the landscape. Ostrich fern loves moist shade or part sun and will even tolerate occasional standing water. It’s ideal along a stream or near a pond. The fronds emerge from a central crown that looks like a dark brown, dead clump on the ground in the winter. This is the fern that has the tastiest fiddleheads and are as prized as asparagus in the spring. Ostrich fern can become invasive sending out new underground shoots so don’t put it somewhere it doesn’t have a little room to spread. If they do spread too much they are easy to dig up and share with a friend.

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Lady fern (Athyrium filix-femina)

Lady fern (Athyrium filix-femina): Lady fern is one of the most common ferns in wooded areas of western New York and also one of the easiest to grow. It prefers moist, loamy soil and shade to partial sun. Lady fern stays 16-36 inches tall and it has an attractive, lacy appearance. It forms a lovely amorphous clump that won’t take over your garden and adds a feathery texture.

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Cinnamon fern (Osmunda cinnamomea)

Cinnamon fern (Osmunda cinnamomea): This is a spectacular, rounded clump forming fern that gets 30 to 60 inches tall. Its fiddleheads are hairy and very decorative in spring. The spore fronds turn cinnamon colored when mature, hence its name. Unfortunately they don’t persist through the season but die back after releasing their spores, but they’re a show-stopper while they last. Cinnamon fern prefers moist to wet soil.

Maidenhair fern (Adiantum pedatum): The maidenhair fern is one of our most beautiful native ferns, always lovely in a landscape. Its fronds unfold on wiry, delicate black stems. The green fronds form a double-sided swirl of leaves from the top of the stem. Maidenhair ferns grow 12 to 20 inches tall and prefer partial to full shade. They thrive in moist well-drained soil. This is not a fern that will grow in standing water. One of my favorite features of maidenhair fern is the deep burgundy color they turn in fall. Stunning!

Sensitive fern (Onoclea sensibilis): This is one of the ferns that will do well in full sun if the conditions are moist. It will also do very well in shade with normal garden soil. Sensitive fern has a pale green color and a single stemmed triangular frond with segments more coarsely divided. The spore fronds persist and look like little round balls on a stick. For this reason they are often used in fall arrangements. Sensitive fern grows to a height of 12 – 36 inches tall, and spreads readily given the right conditions.

Interrupted fern (Osmunda claytoniana): The growth habit of this fern is striking. It forms an upright clump similar to an ostrich fern but the spores appear as dark sacks mid-way up the stem, hence the name. People always ask what it is when they see it in my garden. Interrupted fern grows 24 to 48 inches tall and can tolerate relatively dry shade to partial shady conditions.

If you have the appropriate spot, give one of our native ferns a try. They will reward you with beauty throughout the growing season and for years to come.

Lyn Chimera is a master gardener with Erie County Cornell Cooperative Extension.

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diplodia tip blight

By Rob Barrett

Many years ago, Pinus nigra or Austrian pine, became a staple in upstate New York landscapes. It was thought to be a perfect specimen, with deep green needles and symmetrical growth. It adapted to many different growing conditions and was salt-tolerant. It seemed to be relatively insect- and disease-resistant. We planted it everywhere: lining our yards, commercial properties, hedgerows, and housing complexes, very often in large clumps and too close together considering its mature size.

Traveling through our community today, you will see these trees in many stages of health. Some still look perfect, but not many. Others are almost completely bare with a few green needles at the top and a thick layer of brown needles on the ground below. Mostly, you will see mature trees with very thin foliage 50% to 75% up the tree with some green and brown above.

What happened to our perfect tree? The same thing that usually happens. We find something new and different. We over-plant without diversification. Everything is grand. Then we realize we have made a mistake.

Austrian pines have succumbed to a variety of diseases, compounded with harsh and highly variable weather conditions. Fungal pathogens that manifest themselves as tip and needle blights seem to be our biggest threat. There is a laundry list of these pathogens; we tend to suspect Dothistroma and Diplodia. As with most of fungal plant diseases, they thrive in wet weather, via splashing and dripping. You can see how these diseases might spread like wildfire, considering the trees are planted atop one another and our weather is conducive to optimal disease production.

What can we do? For trees that are already severely infected, removal is the best option.

However, if you’re up for the commitment there are a variety of treatments including spraying with registered fungicides at regular intervals in the spring. Timing, weather, pesticide regulation all hinder this approach. Another option is trunk injections with labeled products. Although these treatments provide some disease suppression, it should also be stated that they are by no means a cure and usually need to be repeated yearly.

Where practical prune out dead branches and rake up and destroy infected needles that have dropped. Water and lightly fertilize trees as needed. Trees 15 years or older are much more susceptible to these issues. As trees mature, reduce any other stresses including insect damage and water management. These added issues often compound the problem and accelerate decline.

Horticultural changes may be our best option. Preemptively remove trees that are unhealthy or thin out those that were planted too close together. Note that when looking at a group of Austrian pines you’ll see differences in their appearances because they’re raised from seed and this means there’s natural variation in resistance from plant to plant which can work to your advantage. When thinning out a stand of trees remove the worst and keep the best.

In a short time this tree has gone from the most-planted list to the do-not plant list. This may be a bit severe; there is a place for Austrian pine in the landscape. The answer lies in diversification. Plant a variety of trees. There are many other choices if you desire evergreens, but they all have their issues. Some good options are Norway spruce, white pine, and even some of the newer long needled pines that are showing some promise. Check with your nursery or consult an arborist for other varieties and planting recommendations.

Trees are an investment. Choose wisely and you will receive a strong return.

Rob Barrett is the manager of Plant Health Care at Ted Collins Tree and Landscape in Victor, NY.

Image of Diplodia on Austrian pine courtesy Ward Upham, Kansas State University, Bugwood.org.

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By Janet Allen

John Allen marveling at the luxurious growth of a large patch of knotweed along a road near our home in Syracuse, NY. Each time we pass this knotweed stand, we remark on its continuing growth and, so far, unchallenged spread along more and more of the roadside.

John Allen marveling at the luxurious growth of a large patch of knotweed along a road near our home in Syracuse, NY. Each time we pass this knotweed stand, we remark on its continuing growth and, so far, unchallenged spread along more and more of the roadside.

My husband, John, has an enemy – a persistent, aggressive one, taller than he is – up to 10 feet or more. After battling this foe on our church grounds for an entire summer, he believes he may be conquering it, albeit slowly. That enemy is Japanese knotweed (Polygonum cuspidatum, or Reynoutria japonica) also known as fleece flower, crimson beauty, Mexican bamboo, or reynoutria. Those who know it most intimately call it “killer bamboo.”

Japanese knotweed was introduced from East Asia to the United Kingdom as an ornamental plant in the early 1800s, and from there to the United States in the late 1800s. Despite its “bamboo” characterization, it’s actually a member of the buckwheat family. This upright, shrub-like perennial has smooth stems, swollen at joints where the leaf meets the stem. Its large leaves are somewhat heart-shaped. Its sprays of tiny greenish-white flowers in summer are followed by small winged fruit containing lots of tiny seeds.

Japanese knotweed has invaded disturbed areas of the eastern U.S., some Midwest and western states, and even Alaska. It tolerates a wide variety of conditions, including full shade, high temperatures, and high salinity. Although it tolerates drought, it’s often found near water sources.

It spreads primarily by rhizomes, but it can also spread by water- or wind-borne seeds. It can even sprout from discarded cuttings. It spreads quickly and crowds out native vegetation, even more aggressively than most invasives. It’s extremely persistent. And it’s tough, having been known to push up through pavement or disrupt house foundations. It greatly alters native ecosystems.

Knowing what a nasty plant this is, imagine our horror when we saw it featured in a garden tour a few years ago! A professional landscaper had actually installed this monster – and some garden center had actually sold it! Any of the native alternatives listed in the sidebar would have been at least as beautiful in that landscape.

The USDA’s National Invasive Species Information Center offers an online video at invasivespeciesinfo.gov/plants/knotweed.shtml. (Oddly, the video features Gabriel Fauré’s lovely Pavane as background music; Paul Dukas’ Sorcerer’s Apprentice would have been more appropriate.)

Eradicating knotweed

There are many ways to attempt to eradicate knotweed. A brief overview of some methods is described below, but if you’re preparing for battle this year, it would be wise to further explore the details as you plan your attack. You probably will need to use more than one of these methods and definitely over a long period of time. As one commentator put it, “Prepare to make its eradication your new hobby.” And remember, cuttings can regenerate, potentially spreading the problem beyond your yard, so regardless of the methods you use, thoroughly dry or burn any stalks or rhizomes prior to disposal.

Smothering is one approach. Cut down all the old canes, and cover the patch with a large, sturdy tarp or overlapping tarps. This method has the virtue of being organic and also offering the possibility of gardening in raised beds right on top of the tarps. You might as well garden on top of them. Research suggests that rather than dying, knotweed has the capability of going dormant for up to 20 years or possibly longer.

Another method is to apply glyphosate as a foliar spray in late summer or early fall – or even repeatedly throughout the growing season to slow it down.


 Want to do good AND eat well? Check out this recipe sent in by the great Kimie Romeo for Apple and Knotweed pie. Not even kidding.


A third method is to dig out the rhizomes, attempting to get every bit, since it can resprout from even the smallest piece left in the ground. Of course, it’s not likely you’ll get every bit since the rhizomes of an established stand can spread 12-15 feet and 6-9 feet deep. Some advise against this method since—besides being a lot of work—it spreads the rhizome fragments and disturbs the soil, making it easier for new knotweed to get established.

A local nature center appears to have had some success with another method. They immediately cut down any emerging sprouts throughout the entire growing season, with the goal of starving it to death.

Inspired, my husband faithfully traveled to church with his scythe each week last summer. He scouted for each new sprout popping up and chopped off its little head. As doubts crept in toward the end of summer, he escalated the battle, carefully applying glyphosate on the cut stems.

He has engaged his enemy on the church ground battlefield again this year, (somewhat) confident of eventual victory. And he has changed his method. Instead of cutting down emerging shoots, he’s pulling them out. He claims the knotweed is much less vigorous this year than last and predicts that after this year, he’ll need only to monitor the area occasionally. In fact, he’s already making plans to use this reclaimed area for native plants.

Who will win – my husband or the killer bamboo? Wifely loyalty demands that I bet on my husband, but more objective onlookers may have doubts. Poor guy. I’d better have a nice cup of tea waiting at home for him.

Native alternatives:

New England Aster (Aster novae-angliae)

Blue False Indigo (Baptisia australis)

Sweet pepperbush (Clethra alnifolia)

Silky dogwood (Cornus amomum)

Sweet Joe-Pye-Weed (Eupatorium purpureum)

Queen-of-the-Prairie (Filipendula rubra)

Virginia sweetspire (Itea virginica)

Maleberry (Lyonia ligustrina)

Fragrant sumac (Rhus aromatica)

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Spider flower (Cleome hassleriana) is a common, welcome volunteer. Photo by Larry Decker

Spider flower (Cleome hassleriana) is a common, welcome volunteer. Photo by Larry Decker

By Michelle Sutton   My friend Bill likes to say that, for both people and plants, “Volunteers are happiest.” Every year dozens of volunteer vegetable and flower seedlings emerge in my community garden plot, popping up conveniently in corners and inconveniently in the middle of paths.   Either way, I’d always assumed that as volunteers likely reverting to characteristics of one parent over the other (“reverting to type”), their flavor or beauty would be inferior, and I’d rogue them out. But I’m rethinking that now. Last year, volunteer snapdragons were quite showy, and I had some very tasty butternut squash from a volunteer plant.

Queen Anne's lace in the Coyne/DiNezza garden is embraced as one of the garden's signatures. Photo by Craig Coyne

Queen Anne’s lace in the Coyne/DiNezza garden is embraced as one of the garden’s signatures. Photo by Craig Coyne

With regard to plants of all types, how do we decide the fate of our volunteers? I asked for observations from popular garden writer, consultant, and speaker Sally Jean Cunningham (www.sallycunningham.org); from the co-creator of a multi-acre plant-lover’s paradise in Scottsville, Jim Lesch; and from Rochester Civic Garden Center trustee and owner of Perennial Designs (garden design & consulting), Milli Piccione.

Sally Jean Cunningham: As I have matured as a gardener, I am sadder but wiser about volunteers. I do remember being the young vegetable gardener who cheerfully welcomed a bit of “free” mint (Mentha sp.), imagining mint juleps and believing I had room for a few plants. Truth is: there is no such thing as a little mint.   That’s also true of most volunteer plants. The volunteer maple tree sapling is probably a Norway maple (Acer platanoides, an undesirable invasive plant) and not a coveted sugar maple. The yellow iris that appeared next to the pond is a thug called Iris pseudacorus. And I remember a near disaster when I was working around a free Angelica archangelica (I thought) and a gardening friend pulled me away—as if from an oncoming train—because it was a giant hogweed! So be careful—there is rarely a free, desirable plant.   There are exceptions to my cautionary approach, however. In my companion-style vegetable garden, where flowers and herbs are mixed among the vegetables, I have always allowed several volunteers to remain. Asters (Aster spp.), milkweed (Asclepias spp.), Shasta daisies (Leucanthemum x superbum), and seedlings from last season’s cleome (Cleome spp.), dill (Anethum graveolens), or love-in-a-mist (Nigella damascena) are all great for pollinators or other beneficial insects.   In the Coyne/DiNezza garden in Buffalo (a popular stop on the Snyder-CleveHill Garden View and AAA Motorcoach tours), the gardeners willingly permit Queen Anne’s lace (Daucus carota) to pop up intermittently, quite aware that removing them can be a chore. In this garden, their airy little heads, waving among traditional perennials, have become part of the Coyne/DiNezza garden’s signature.

Jim Lesch: Richard LeRoy and I converted several acres of former farmland in Scottsville to gardens. Behind our property there are still farm fields, hedgerows, and woods. From that reservoir, native plants come unbidden in their effort at succession back to forest. We find volunteer honeysuckle (Lonicera spp.) and dogwood (Cornus spp.) shrubs on a regular basis. We keep a handful of these at the edge of our property to blend visually with the hedgerows in the distance.   In the last five years, junipers (Juniperus spp.) have also appeared; these could be either volunteers from native junipers or our own ornamentals reverting to a parent juniper species. We have relocated and kept most of these. They are a bit rangy, but they do have an interesting bluish cast and tight columnar shape. To us they seem more vigorous and likely to survive on our alkaline soil than the named ornamentals we have introduced.   Besides the “volunteers” coming from the fields (and dandelions from our neighbors), some of our ornamentals also spawn volunteers. For instance, many of our maples have sown profusely. We removed a nearly mature Norway maple to end its invasive ways. A hedgerow of Amur maples (Acer ginnala) and a single paperbark maple (A. griseum) have reproduced widely and are thus weeds as far as we are concerned. On the other hand, we were delighted that one of our miniature Japanese maples (A. palmatum) seeded itself close by. We will dig and site it elsewhere or give it as a gift.

Tall verbena (Verbena bonariensis) can create a beautiful stand if allowed the space to reseed with abandon. Photo by Michelle Sutton

Tall verbena (Verbena bonariensis) can create a beautiful stand if allowed the space to reseed with abandon. Photo by Michelle Sutton

A few of our yews (Taxus spp.) seed themselves. We are often unsure whether the new plants are going to be spreading or upright yews, since we have both in our gardens. Pine (Pinus spp.) and spruce (Abies spp.) seeds also occasionally sprout. It is a joyous feeling to see Mother Nature doing so well on our reclaimed agricultural land, but often we cull these offspring to avoid ending up a forest rather than a garden.   Among perennial flowers that spread, the winners in our garden are undoubtedly the violets (Viola spp.). We remove literally four to six wheelbarrow loads from our planting beds each year. If we did not do this, many other perennials could not survive due to unrelenting competition from the violets.   The short woodland grasses and the Northern sea oats (Chasmanthium latifolium) we’ve planted have volunteered here and there and seem to cheerfully tolerate not just some shade, but dry clay. Last year we removed most of a stand of sea oats to make room for other plants, but we still have some to enjoy. We planted ajuga (Ajuga spp.) in partial shade. It kept sowing itself some feet away in the lawn. Over the years we have removed these volunteers several times to establish ajuga elsewhere.

Milli Piccione: I started gardening in earnest in my early 30s. My naive vision was that the gardens were going to be orderly, wellthought out, and totally under my control. After the first season of obsessed planting and weeding, I started to relax ‘just a bit’ and observe and appreciate the habits of my perennials and annuals.   I also began to realize that Mother Nature’s volunteers could sometimes be my allies, not my enemies. The first volunteer of note in my small woodland area was a magnificent biennial—the 5-foot-tall velvety foliaged mullein (Verbascum spp.). I learned that it attracted seed-eating birds and became a believer the next day watching nuthatches zipping up and down the matured flower stalk feasting on the seeds. What a delight!   As I became more experienced and more observant I left select volunteer perennials and annuals in place.In one little section of my rock garden I had planted the dwarf Solomon’s seal (Polygonatum humile) adjacent to a miniature narrow gold-leaved hosta (Hosta sp.). After two or three years, both started to travel and intertwine, forming an utterly charming combination. I’ve tried to recreate this effect in other gardens, the outcome never as successful as nature’s original. Self-seeded annuals and perennials can soften hardscaping as seeds, amazingly, germinate in the cracks and edges of walks and in dry-laid stone walls. The balance between a softening versus an unkempt look is in the vision of the gardener—your garden, your choice.   Self-seeded perennials don’t usually get out-of-hand. Annuals, however, can take advantage of your generosity. My favorites are forget-me-nots (Myosotis spp.), tall verbena (Verbena bonariensis), and nicotiana (Nicotiana sylvestris). These can work if you’re willing to cull them when necessary, especially when the volunteers have to ‘play well with others’. Forget-me-nots are a favorite harbinger of spring—the diminutive flowers form an exquisite pale haze underneath spring bulbs. About three weeks after they have finished flowering, the fresh foliage turns dry and nasty looking. Rip out every plant once the seed has ripened; as you pull the plants you’re automatically broadcasting seed for the following year.

Nicotiana (Nicotiana sylvestris) is one of garden designer Milli Piccione's most valued volunteer annuals. Photo by Milli Piccione

Nicotiana (Nicotiana sylvestris) is one of garden designer Milli Piccione’s most valued volunteer annuals. Photo by Milli Piccione

Tall verbena and nicotiana are 3 and 5 feet tall, respectively, and are both prolific self-seeders. Choosing which seedlings to keep depends on their neighbors and the final effect you want in your garden. The verbena is narrow with delicate purple flower heads that appear to float; it attracts monarch butterflies and other pollinators. Tall verbena is easy to tuck into existing beds, taking up little horizontal space. The opposite in its demands is the nicotiana—one plant can be 5 to 6 feet tall with 2-foot-long leaves and fragrant tubular white flowers. If you have the space they are magnificent as long as you are merciless when thinning, because they can easily shade out smaller plants.

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Natural Selections: Birches & Their Kin

by janem on March 17, 2014

Andrew Fowler

Story and images by Andrew Fowler

Birches (Betula spp.) are among the most cold-hardy of deciduous trees, being natives of the northern boreal forests alongside firs and spruces. During the glacial periods, birches remained close to the glaciers’ edges, and once those glaciers retreated birches became the pioneer species. Today they prove themselves good colonizers of disturbed soils, highway cuts and abandoned agricultural fields, and can serve as nurse trees for other species. They are usually short-lived, except perhaps for the yellow birch (B. alleghaniensis), which maintains its presence with beech and maple among climax forest communities along the Appalachian chain and throughout the northeast and Great Lakes.

Birches are noted for their colorful, peeling bark, with white being the most commonly associated feature. It was this asset that brought birches into the gardeners’ world—unfortunately, the European white birch (B. pendula) became the birch of choice, while the native species were all but ignored. The problem with most birches is that they are denizens of cold northern forests, and placing them in manicured landscapes and lawns is almost inevitably going to stress them. The European white birch soon proved to be highly susceptible to the bronze birch borer, a native beetle that feeds on the cambium of stressed trees and generally proves fatal. The native paper birch (B. papyrifera), also a white-barked species, is less susceptible to the beetle. However, this species likes a cool, moist acid soil, a rare commodity in most landscapes. The determining factor in bronze birch borer resistance is the presence of the chemical rhododendrol, produced in stressed and dying bark tissue in all white-barked species of birch, which is a strong attractant to egg-laying female borers. There are two native birches that do not produce rhododendrol and are thus resistant to the borer: the sweet birch (B. lenta) and the river birch (B. nigra). Leaf miners are also a major problem on white-barked species, but not for sweet and river birch.

All birches have alternate, ovate, pointed leaves with finely serrated margins on thin reddish-brown branches. Fall color is usually a golden yellow. All are monoecious with separate male and female flowers formed in the fall but remaining tight until spring. The female flowers are upright and enclosed in a bud. When open they look like small cones. Male catkins are pendulous and clearly visible through winter, looking like little tails hanging from the branch tips. Flowering takes place in April, when the catkins expand and open to shed the pollen, which is windborne and can be an allergen for some people. The seeds are small and winged and are dispersed during the winter as the small cones disintegrate.

Birches prefer moist acid soils that remain fairly cool. They have fibrous root systems, which makes for easy transplanting. Fall transplanting is not recommended, however, because their thin bark and abundant twigs make water conservation through the winter difficult. Transplanting in the spring before bud break is the best time. However, they readily sprout from the base if cut down, and can be rejuvenated this way.

Birches are “bleeders” and should not be pruned in late winter or spring, but rather right after leaf drop in the fall. They can be tapped in the spring for their sap, which is used to make birch beer. Often frozen sap can be found during the winter months hanging from storm-broken twigs, and these make good popsicles.

As mentioned above, the white-barked species are particularly prone to problems due to environmental stress, notably attacks by birch bark borer and birch leaf miner. However, there are two species, native to the eastern United States, which are fairly resistant to both pests. These are the sweet birch (B. lenta), also known as cherry birch or black birch, and river birch (B. nigra).


   Sweet BirchSweet Birch

Native from New York to Maine and down the Appalachian chain to Georgia, the sweet birch is hardy to Zone 3, and is better adapted to cultivation in warmer climes than the white-barked species. This species is a fast grower and reaches a height of perhaps 50’ and a span of 35’, and is distinctly upright in youth. The bark is a rich red-brown with prominent horizontal lenticels, reminiscent of cherry bark, becoming almost black and scaly with age. The young stems are thin and reddish brown and strongly smell and taste of wintergreen when bruised or chewed, which makes for easy identification. Yellow birch (B. alleghaniensis) also has a wintergreen odor but is not nearly as strong. The leaves of sweet birch are ovate, sharp pointed and finely serrated. Glossy green in summer, they turn a rich golden yellow in the fall, perhaps the best of all the birch leaves for fall color. The male flowers form in the fall and persist through winter hanging from the terminals, expanding and opening in April before or with the unfurling leaves. The pistillate flowers are held upright lower on the branches and open in time to receive pollen in the spring. The pistillate flowers develop through the summer into strobiles, resembling small cones, holding the small winged nutlets, which are dispersed through the winter.

This species does well on moist, fertile, acidic soils with good drainage, but will also tolerate dry soils once established. Full sun is best but it will also tolerate a modicum of shade. Poorly drained soils should be avoided.

The lack of papery, peeling bark has relegated this species to obscurity, resulting in a complete lack of cultivars, but I find it has a charm of its own, and certainly has the best fall color of any birch. It is definitely worthy of more attention.

River birch barkRiver Birch

The river birch is the only birch native to the warmer regions of the eastern United States, ranging from Massachusetts to Florida and west to Texas. It is a denizen of riverbanks and floodplains subject to periodic flooding. This makes it a good choice for wet areas of the landscape, but the species can also tolerate dry soils, at least for short periods. Its heat tolerance also makes it more easily incorporated into urban landscapes. Soils should be on the acidic side, or chlorosis can develop. The bark of this species is creamy and shiny on young stems, becoming papery thin and peeling off in curls, revealing pinkish and orange red patches underneath. It is perhaps the most colorful of the birches. The leaves are wedge-shaped, coarsely serrate or lobed, and pointed. The fall color is yellow, but is rather dull compared to the sweet birch, and the leaves often drop very early. It grows quickly to a mature height of about 60’, being pyramidal in youth. It is commonly multi-trunked, which serves to show off the bark.

Because of the widespread adaptability of the species, there are a number of cultivars now available. Probably the most frequently encountered is Heritage® (‘Cully’), which is a patented selection from Heritage Trees Inc. of Illinois. It displays increased vigor, with larger, glossier leaves and whiter bark than the average river birch. Other notable cultivars are Fox Valley® (‘Little King’), a compact, bushier grower to about 15’, and ‘Shiloh Splash,’ a variegated shrubby form to about 10’, with white edges to the leaves.

Like sweet birch, river birch is essentially immune to birch bark borer and highly resistant to leaf miner, and makes an excellent landscape specimen. Of course, as with any monoculture, the more they are planted, the more likely a pathogen is to appear. Diversity in the landscape is the key.

There are a few other members of the birch family (Betulaceae) worth considering for the garden. These include hornbeam (Carpinus spp.), and hophornbeam (Ostrya spp.).

Hornbeam in FallAmerican Hornbeam

The most common hornbeam in landscapes is the European or common hornbeam (C. betulus). Long used in Europe for hedges and screens, it takes pruning very well and is sometimes pleached into pergolas and arbors. It retains its brown dead leaves through winter, like the European beech (Fagus sylvatica), thus adding to its value as a screen. The fastigiate varieties are also highly prized. The native American hornbeam (C. caroliniana), on the other hand, is virtually ignored by the gardening public, while offering many of the same features as the European species. Native to the eastern half of the United States from the Great Lakes to Florida and hardy to Zone 3, the American hornbeam also goes by the names musclewood, blue beech and ironwood. An understory species of wooded lower slopes and floodplains and commonly associated with witch-hazel (Hamamelis virginiana), it is usually a multi-stemmed tree that can reach 30’, but can be trained as a single trunk. The stems have a fluted sinuous look, resembling well-muscled arms, and the smooth blue-gray bark accentuates this. The leaves are ovate and pointed with a doubly serrate margin. New leaves tend to be bronzy to reddish, becoming dark green in summer and turning yellow, orange and red in the fall. It has better autumn color than the European species, but does not hold its dead leaves through the winter.

The male flowers are in catkins hanging from the tips of twigs, like birches. Female flowers are low on the branches and are short, each ovary set in a papery three-lobed bract. These become nutlets arranged in a hanging infructescence, 2 to 4” long, which resemble hop fruits. The fruits gradually disintegrate through winter, spreading their papery seeds.

Hornbeam barkThe wood is very hard and was used to make tool handles and mallet heads. It can be polished very smooth to resemble horn. The name hornbeam probably derives from this characteristic, while “beam” comes from the German word “baum,” meaning tree.

Hornbeams like deep moist acidic soils, even seasonal wet sites, but can adapt to drier soils and those with a higher pH. Although shade-growing in nature, they can also grow in full sun, where they will be much fuller branched. Generally, they are pest-free, although fusarium cankers can be an issue with stressed trees. They have a deep, coarse root system, consequently fall transplanting is not recommended; springtime is best. A delightful small native species, the American hornbeam deserves more attention from gardeners.

 

 

 

Hophornbeam barkAmerican Hophornbeam

In the same woods as the American hornbeam, in the higher, drier slopes, the hornbeam disappears and American hophornbeam (Ostrya virginiana), the other ironwood, appears. Covering the same geographic range as the hornbeam and hardy to Zone 4 (possibly 3), the hophornbeam is usually a single trunk, growing straight and tall to about 40’. Unlike the smooth gray bark of hornbeam, the bark of hophornbeam is shiny dark brown on young stems and shaggy gray on older trunks, which makes for easy identification. The leaves are similar to birch and hornbeam, although a little wider, with doubly serrate edges. The fall color is a muted yellow and rarely effective. The flowers are like those of the other species discussed, with male catkins, grouped in threes, hanging from the tips and smaller female flowers hidden below in the foliage. In the fall, a nutlet is formed, enclosed in a papery pod, several being strung together to resemble the fruit of hops; hence the common name. These dry and persist through much of the winter and can also be used to identify the tree. The fruits have tiny hairs, which can irritate the skin.

Like the birches and hornbeams, the hophornbeam is a bleeder, so pruning should be done in fall or winter. Like most trees, moist acidic soils are preferred, but the hophornbeam can also tolerate dry soils. It’s a tap-rooted species, so container-grown trees are easier to establish. Full sun will produce a dense canopy, while in shady situations an airy open structure is more usual. The wood is extremely hard and strong, resistant to ice storm damage, and has been used for making airplane propellers and sleigh runners. Hophornbeam makes for a tough, dependable small tree, with very few pest problems

The birch family provides opportunities for most garden situations, from dry shade to open sunny areas and even wet soils. Winter interest is available in the colorful barks of some species and the hanging catkins. Fall colors come in reds, oranges and yellows. The fruits of these species provide food for small birds, such as chickadees, and small mammals.

Andrew Fowler operates Holmes Hollow Farm nursery and Christmas tree farm in Victor, NY.

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Woodies, Pots, and Winter: Why and How

by janem on November 13, 2013

MIchelle Sutton

Story and photos by Michelle Sutton

Recently, I visited several small artsy towns seeking to photograph woody plants that are overwintering in pots or elevated planters in front of restaurants, galleries, and yoga studios. I had the impression that many of the successes were happy accidents; someone had a little boxwood or dwarf Alberta spruce, they stuck it in a pot, and the little champ survived the winter outdoors. The most striking example was a catalpa tree (Catalpa speciosa), fifteen feet tall and several inches in caliper, somehow flourishing in a tiny concrete container in a veterinarian’s parking lot.

catalpa in planter

Catalpa
There must be an interesting backstory as to how this catalpa tree came to grow in this container—tree-to-container proportions not recommended …

When they’re set off in some way, such as marking both sides of a passageway, potted trees and shrubs give us a sense of order and rightness. You can do this with a pot of pansies or impatiens, but the effect isn’t quite as soaring.

Besides marking entrances, there are other reasons to use woody plants in pots. There is the sensual pleasure of having woody plants nearby, the focal points they create, the portability, and the deer thwarting. In pots close to your house, deer-vulnerable shrubs like arborvitaes enjoy a safe(r) haven.

You can also festoon potted trees near the house with holiday lights. One client kept three trouble-free junipers (Juniperus chinensis ‘Hetzi Columnaris’) for holiday lights in pots on the porch for five years before transplanting them out into the landscape, where they now make a beautiful buffer between neighbors. In highly urban situations where there is often a sea of concrete, a potted tree or a planter with multiple woodies bring welcome islands of green.

There are functional challenges pots can rise to. One client had a deck beyond which was a hillside of tangled ground cover that neither of us had the hubris to try to clear. Instead, we brought trees and shrubs into her living space on the deck. She wanted to have the feeling of a multi-layered garden (trees, shrubs, perennials, and annuals), but with a clustered collection of pots. We thought the woody plants in the deck garden should return each year for a good many years to justify their expense.

The trees and shrubs we picked for her had to be tough characters, because they might not get watered enough by this busy lady. So they had to be species that are tolerant of dry conditions. The woody specimens also had to be sufficiently cold hardy to overwinter in their pots outdoors. We didn’t want to have to move these heavy pots indoors every fall, nor did we want to be bothered with wrapping things up in ugly burlap. We tried out everything from hydrangeas to elderberries, with a high rate of success. Our first limiting criteria: winter hardiness.

Cold Considerations 

You can see your USDA Hardiness Zone at planthardiness.ars.usda.gov. I live in Zone 6a, which means that the average extreme minimum low in the winter is -10 to -5 F. A woody plant’s stems are just as hardy in a pot as in the ground, but a plant’s root systems are significantly less cold hardy than its above-ground parts. When you plant in pots, or any planter that rises above the ground, the roots are exposed to colder ambient temps. In the earth, roots enjoy the temperature moderation provided by soil.

A rough guideline is that your plant selections for pots or elevated planters need to be hardy to at least two zones colder than your USDA zone. So in my case (zone 6a), in general, I’d want to use woody plants that are hardy to at least Zone 4a for any pots that I want to overwinter outdoors.

Here are some evergreen and deciduous woodies that have worked well for me in overwintered pots. They are all hardy to at least Zone 4a. It’s helpful to buy trees that have been propagated and grown in your region, by the way, because their local provenance ensures that they are adapted to your winters.

 

Evergreen

boxwood in planter

Boxwood
Boxwood for containers can be risky in terms of winter hardiness, but you might give it a go if you have a protected spot and a notably hardy variety.

Boxwood (like Buxus ‘Wintergreen’, which some sources cite as hardy to zone 4, others to zone 5 only), arborvitae (like Thuja occidentalis ‘Little Giant’), junipers (Juniperus sp.), and spruces (Picea sp).

Juniper in pot

Juniper
Junipers are among the hardiest of the evergreens and coveted for their drought tolerance as well.

Deciduous 

Dwarf rugosa roses (Rosa rugosa)

Elms (dwarf) (Ulmus sp.)

Baldcypress (dwarf) (like Taxodium distichum ‘Peve Minaret’)

Elderberry (like Sambucus ‘Black Lace’)

Ninebarks (like Physocarpus ‘Summer Wine’)

Black locust (like Robinia ‘Twisty Baby’ with awesome contorted branches)

Hydrangea paniculata (like ‘Limelight’)

Lilacs (not all, but many—check the label for hardiness zone)

Upright buckthorn (Rhamnus frangula ‘Fine Line’)

 

Here are some woodies I’m looking forward to trying in overwintered pots:

‘Northlight’ dwarf dawn redwood (Metasequoia glyptostroboides)

‘Robusta Green’ juniper

Dwarf ginkgo (Ginkgo biloba ‘Troll’)

Purple beautyberry (Callicarpa dichotoma) (hardy to 5a)

Knockout roses (zone 5)

‘Golden Spirit’ smokebush (Cotinus coggygria)

You may have areas around your home that are microclimates where you can get away with using potted plants a half or whole zone less hardy—in my case, plants with hardiness only to Zone 5a or 5b. Like all facets of horticulture, testing winter hardiness limits can be regarded as an experiment and an adventure!

Mixed Media 

Cornell Urban Horticulture Professor Nina Bassuk says we should choose soil-less potting mix over “topsoil” or field soil of any kind. (She points out that simply calling something “topsoil” is a meaningless designation, by the way—anyone can call their product that, even if it’s junk.) Soil-less media like those using peat or coir (ground coconut hulls) are highly porous and designed to allow water to drain freely out of pots, while field soil in containers perches—i.e., hangs on to water too tightly.

A good mix will feel light and friable in the bag. Don’t be surprised that it’s actually a bit hydro-phobic at first: it takes a certain amount of water saturation to penetrate all that pore space. Once your trees and shrubs are potted up, water them deeply once or twice a week during the growing season. Less frequent but deeper watering is more effective than frequent shallow watering. Smaller pots will need to be watered more often than larger ones.

Bassuk says that the pots should be watered well before going into the winter. For one thing, well-hydrated woody plants are less prone to desiccation by winter winds. At the beginning of winter, she recommends moving the pots as close to the house as possible and ganging them together so the sides are touching. “The warmth of each pot insulates its neighbor,” she says.  “You could also stack straw bales around them to further insulate them.”

The best containers for overwintering are salt-glazed pottery and plastic. Ceramic, lightweight foam, and terra cotta pots are the most likely to crack under the freeze-and-thaw pressure of our winters.

Time to Move Out

If a tree or shrub is well cared for in its container, it may outgrow its space. This will take a long time in the case of dwarf woodies. (By the way, “dwarf” means grows very slowly, but doesn’t necessarily stay small—for plants that stay little, see the “miniatures.”) You can prune the stems of shrubs and multi-stem trees to keep top growth in check, but this is not advisable for trees with one central leader.

For smaller potted plants whose roots have fully colonized the pot and clearly want to break out, you can transplant them into larger pots. More brutally, you can prune an outer rung of roots and then replant in the same pot, but this kind of root reduction is stressful on the plant.

For vigorously growing woodies, I transplant into successively larger pots and then at some point make the decision to move them into the landscape. Often this is after many years of service as a containerized woody element of a mobile, elevated, and elegant pot garden.

'Summer Wine' ninebark

Summer Wine ninebark
Ninebarks (like ‘Summer Wine’, hardy to zone 3) can make good shrubs for containers and planters.

 

pine tree in planterPine tree
Just as in the larger landscape, a containerized pine can be expected to shed some needles in the fall.

 

 

dwarf alberta spruce

Dwarf Alberta spruce
While dwarf Alberta spruces have some liabilities, they are very hardy for containers.

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Natural Selections: Invasive Species

by janem on September 5, 2013

Invasive Species

By Rich Finzer

One of the greatest strengths of any woodlot, forest or open stretch of ground is its biodiversity. The greater the variety of species, the less chance disease or insects will ravage the entire area. Ironically, biodiversity may also become a glaring weakness, particularly if land begins hosting invasive species. Here in Cayuga County, we’re plagued by several of these invaders and unfortunately we’re not alone. Many invasive plants range across wide swaths of the U.S. Of the time spent managing my woodlot, a good portion is devoted to eradicating these unwelcome and often alien pests.

Japanese honeysuckle (Lonicera japonica) is a perfect example. Introduced into the U.S. in 1806 to help combat soil erosion, no one anticipated how invasive the plant would become. On my farm, the shrubs proliferate where the cropland meets the edge of the woodlot. Every spring, while the ground is soft, I make a concerted effort to rip out as many as I can. Fortunately, the shallow rooted honeysuckle is easy to identify and easy to dislodge. [We had a hard time with the italics in this story and decided to just omit them. You know where they go. —Ed.]

Japansese honeysuckle
Japanese honeysuckle

The flowers, which occur in pairs, range in color from pure white to a creamy whitish-yellow. The ovate leaves are set opposite on the woody branches. Following pollination, each bloom produces a black berry containing a single seed. As birds eat the fruit, the seeds are deposited in their droppings, accounting for the speed with which the plant can overtake an area.

One of the other invasive trees I regularly confront is white mulberry (Morus alba). Native to China where it is used to feed silkworms, it was introduced during colonial times as our British masters tried to establish a fledgling silk industry. The trees produce a tart edible fruit about the size of a raspberry. Wild birds, especially robins and bluebirds consume them and deposit the seeds in their droppings. The plants are stubborn to remove, and even if cut off at the ground line will often re-sprout. While I like songbirds, I’m no fancier of white mulberry. The only sure-fire method I’ve found for completely killing one is cutting it flush with the ground and then auguring a hole into the center of the stump. Following that, I insert a funnel filled with bleach. Once the roots absorb the bleach, it’s curtains. [While this is undoubtedly an effective method, using bleach—or any substance not labeled an herbicide—to kill plants is actually illegal, and we therefore cannot recommend it. —Ed.]

White mulberry with berries just beginning to ripen
White mulberry with berries just beginning to ripen

Another invasive species is Russian olive (Elaeagnus angustifolia). Native to southern Europe, it was brought to the U. S. during the late 1800’s. Like other introduced alien plants, it too will quickly overtake native trees. Its leaves are slender, shiny on top and a fuzzy olive-gray underneath. The tree produces hundreds of tiny yellow flowers that bloom at the base of the leaves. Following pollination, each forms a small olive-colored fruit roughly the size of a chickpea. The plant prefers partial sun, and removing one can be nasty business, as the branches are armored with 1 to 3 inch thorns. If Russian olive has a sole redeeming quality, it’s that the thorns afford great protection to nesting birds, particularly catbirds. As a nod to my avian friends, if I encounter one, I generally spare it until nesting has concluded. I am not nearly as merciful with wild roses.

Russian olive in blossom
Russian olive in blossom

The wild or multiflora rose, (Rosa multiflora) is another challenging adversary native to China. Brought to the U.S. sometime during the 1700’s, the plant is covered with long, extremely sharp thorns, tough enough to pierce heavy leather work gloves. It proliferates by sending out runners, rooting its drooping canes to the soil and by seeds. According to some biologists, a single plant may produce as many as 17,000 seeds during a single growing season!  If I locate a large one, I attach a cable noose around the main trunk and tear out the entire plant using my pickup. In Midwestern states like Ohio, wild rose is subject to massive state-sponsored eradication programs. According to USDA estimates, it infests as many as 45 million acres. How much land is that?  It’s roughly the combined land area of New York and Connecticut.  I don’t blame anybody for anything they do to eliminate this scourge. Have at it.

Roadside berm infested with multiflora rose Multiflora rose blossoms
Roadside berm infested with multiflora rose; Multiflora rose blossoms

While many invasive plants were imported, one native species, staghorn sumac (Rhus typhina), is equally challenging to control. Classified as a woody shrub, sumacs are shallow rooted and spread by both rhizomes and seeds. After flowering, the familiar rusty-red, fruiting head begins forming. It’s actually a compact cluster of fruits known as drupes.  Drupes measure 1/4 inch in diameter and contain one seed. Interestingly, the germination rate of sumac seeds is enhanced after passing through the digestive systems of rabbits. So if you’ve got lots of sumacs, you probably have a thriving bunny population too. Sumacs prefer sunny locations and are often the first trees to grow on abandoned farmland. The yellow 12-inch flower plumes emerge in early June. By late summer, the ripening drupes take on their trademark rusty-red hue. I’ve found the easiest method of destroying sumacs is tearing them out by the roots.  For larger ones, I sometimes employ my truck and a length or two of logging chain.

Staghorn sumac flower plume Reddish clusters of sumac drupes
Staghorn sumac flower plume; Reddish clusters of sumac drupes

Up until now, the plants I’ve described might be classified as troublesome or stubborn, but giant hogweed (Heracleum mantegazzianum) is justifiably described as vile. It’s extremely invasive and it’s extremely poisonous as well. It’s a phototoxic plant. When exposed to the UV rays in sunlight, the sap from the stalk is capable of burning exposed flesh (a condition known as phytophotodermatitis). If even a small amount of sap gets near your eyes, it may cause blindness! A mature plant can reach a height of 15 feet, and the main flower growing atop the stalk may attain a diameter of 30 inches. Giant hogweed is native to Central Asia, and was introduced into the U.S. during the early part of the twentieth century as an ornamental (what were those idiots thinking?). Classified by the USDA as a noxious weed, it is a perennial and once fully established is nearly impossible to eradicate. Regular mowing keeps it under some measure of control, but for total elimination only two methods are known. The main taproot must be severed about 6 inches below the ground or the plant must be killed chemically. Regrettably, giant hogweed prefers moist soils, particularly along stream banks and gullies, making it difficult to reach. Five summers ago, I discovered a lone plant growing along the bank of the creek bisecting my property. While wearing heavy gloves, heavy clothing and eye protection, I sprayed the entire plant with herbicide. After drenching the entire plant, it quickly perished. [The DEC instead cautions citizens to use only the manufacturer’s recommended dose. For more on controlling hogweed with herbicides, see dec.ny.gov/animals/40961.html. —Ed.] If you encounter a solitary plant as I did, you may be able to destroy it on your own. However, if a large colony develops, you may require the assistance of professionals with their arsenal of federally regulated herbicides. Either way, it must be killed wherever it’s found. The DEC has taken notice of giant hogweed too. Since 2008, a 14-person team regularly attacks and destroys the plants whenever/wherever its presence is reported. To report giant hogweed, contact the DEC’s Hogweed Hotline at 845-256-3111.

Giant hogweed plant over 6 feet tall  Giant Hogweed plant
Giant hogweed plant over 6 feet tall

Rounding out the rogue’s gallery is another streamside pest, the wild grape (Vitis riparia). Also known as riverbank grape, it flourishes along creeks or streams. Growing to an ultimate height of 50 feet, this woody vine looks to surrounding trees for support, growing into the crowns until it smothers them. Found across the entire northern half of the U.S., it’s the bane of landowners everywhere. Small plants may be pulled out by the roots; larger specimens with their shaggy bark should be chopped off at the ground line and the woody vines pulled down.

Newly sprouted wild grape leaves and a bud cluster which will mature into fruit
Newly sprouted wild grape leaves and a bud cluster which will mature into fruit

The beauty of our woodlands, stream banks and fields is something too many folks take for granted. But responsible stewardship requires every landowner to rid their space of any invasive species they encounter.  It’s hard work. It requires persistence, coupled with the enthusiasm of a fanatic; and it’s worth it.

Additional Information: Visit www.usda.gov or the individual websites listed below.

Raised in Chili, NY, Rich Finzer resides on an 80-acre farm near Hannibal. He is a regular contributor to Living Aboard, Life in the Finger Lakes and Dollar Stretcher magazines.

Photos by Rich Finzer

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