September-October 2013

Erin Luchsinger Hull

Erin Luchsinger Hull

This issue’s guest expert Erin Luchsinger Hull, a fourth generation farmer in Onondaga County, where she works as a general agriculture educator for Cornell Cooperative Extension.

Q: I found this vine in my garden. What is it?

Japanese hops
Humulus japonicus =
bad

A: The vine you found is Japanese hops, Humulus japonicus, an extremely invasive and noxious weed. It is an annual not used in beer production, and it should never be intentionally planted.

Humulus lupulus, on the other hand, is an extremely useful plant that many dearly love—and this is the kind of hops for making beer.

Humulus lupulus courtesy flickr: Matt Lavin

Humulus lupulus = good

Here’s an easy way to tell them apart: common hops leaves have three lobes or none, while Japanese have five, seven, or nine.

In the 1880s, 80% of all hops produced in the United States were grown in central New York, but plant diseases and prohibition caused the region to lose its foothold to the Pacific Northwest.

Hops do very well in our climate. They require a lot of water and are prone to powdery mildew, which thrives in moist areas with little air movement. The easiest way to prevent it is to strip the lower leaves from the plant and keep weeds down.

If you plan to grow hops, be prepared. They grow tall and they grow fast. Hops can easily grow to heights in excess of 20′ and poles or trellises should be sized accordingly.

{ 0 comments }

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

{ 0 comments }

Michelle wedding day

by Michelle Sutton

Photos Courtesy Urban Horticulture Institute, Cornell University, Ithaca NY, except where noted.

“Urban Horticulture” sounds exotic and specialized, but it’s perhaps the most broadly applicable branch of horticulture. According to Cornell Urban Horticulture Institute Director Nina Bassuk, urban horticulture used to be called “human-impacted landscapes,” and among the landscapes in which we live, which ones are not greatly impacted by humans.

“Wherever people live,” Bassuk says, “the soil has been disrupted and probably significantly compacted, which reduces oxygen, nutrient, and water availability to tree roots. Frequently, housing construction debris has been buried on the site; buried cement blocks and cement sidewalks alike will drive the soil pH up. Heat is reflected off of buildings, paved surfaces, and cars, putting more water stress on plants. Salts used on paved surfaces run off into the soil, desiccating plant roots. Roots that are in the vicinity of pavement and structures often have limited soil volume to explore.” You get the idea: “urban” stresses, while particularly grievous along city streets, are present to varying degrees in our home landscapes.

One can use urban horticulture principles every day in residential situations to have greater success with plants. Site assessment and proper plant selection techniques are just as relevant to homeowners as they are to city foresters.

Getting Started

You’ll want to bookmark www.hort.cornell.edu/uhi. Go to the publication called “Recommended Urban Trees” (RUT), then go to “Site Assessment Checklist” and the adjacent document about how to complete it. The process of site assessment has you consider things like sun and shade exposure, USDA Hardiness Zone for your area, microclimates (for instance, the south side of your house versus the north), soil texture, pH, and drainage. This is a useful process for considering all types of plant material, not just the trees in RUT.

The checklist in RUT includes visual assessment of existing plants—both cultivated and wild. Noting what’s growing well—and what’s not—will give you insights into the site conditions. For instance, if rhododendrons, azaleas, and mountain laurel have lustrous dark green leaves and other signs of vigor, your soil is probably acidic to some degree. If your red maple or pin oak tree leaves are pale yellow, your soil may be alkaline. If you see girdling surface tree roots on more than one species of tree, there may be drainage and/or soil compaction problems.

This is a very sophisticated, thorough checklist. Will you fill out every box for every situation? No. But using the checklist gets you in the habit of thinking systematically about your site, and then you can engage in some informed plant-site matching. RUT is a great resource for any homeowner who has site challenges (i.e., every homeowner!) It includes profiles of more than 90 tough trees.

Sample Scenarios

This is a matching game. What are the site opportunities and restraints? What kind of tree (or shrub, or perennial) would you like to have? Which one will satiate your need for beauty but also perhaps fulfill practical functions like privacy/screening, habitat for wildlife, or shading your house? Do the site assessment results look favorable for your intended tree?

Scenario A

  • You live in USDA Hardiness Zone 5a.
  • Your soil is a desirable clay loam, easy to dig, and drains well, but you can tell by the kinds of plants growing wild there (or by doing a pH test) that you have a higher-than-average pH.
  • You have a spot in full sun where you’d like to plant a shade tree that will make your back yard more hospitable in summer.
  • There are no overhead wires or underground utilities in the vicinity.
  • You would like something that is drought-tolerant, because the spot you have in mind is far enough from the house that you don’t realistically see yourself dragging hoses out there. (You’ll want to water it in the first few critical years, though, until it gets established—and in drought years).
  • You want something with fabulous fall color.

A good match: RUT has a small tree section and a medium-to-large tree section. For shade trees, we’re looking at the latter. RUT shows that most of the listed red maples and Freeman maples have beautiful fall color, but these maples are not especially drought tolerant. A katsura tree would be beautiful but again, can’t take things dry. A-ha! What about a ginkgo tree (a male cultivar, like ‘Autumn Gold’, with excellent golden yellow fall color)? It can take “prolonged periods of dry soil”, is sufficiently hardy (to Zone 4b), does fine with high pH … we have a winner!

Male cultivars of Ginkgo biloba with showy fall color offer both beauty and, once established, drought tolerance.

Male cultivars of Ginkgo biloba with showy fall color offer both beauty and, once established, drought tolerance.

Scenario B

  • You live in USDA Hardiness Zone 6a.
  • You want a small tree in a pocket garden between your driveway and the front porch. It has to be a small tree because the bed is approximately 15 x 18 feet; there isn’t enough room above or below ground for a bigger tree.
  • It’s the south side of the house, and due to the heat radiating from the house, driveway, and sidewalk, its gets hot and the bed dries out quickly, but it’s near the spigot, and you plan to water the tree.
  • You would like showy flowers.
  • There are no overhead wires or underground utilities in the vicinity.
  • This garden bed gets salt runoff from the sidewalk.

A good match. It’s challenging to find something small enough to fit this spot, but there is a whole page of compact crabapple cultivars in RUT that would do nicely, ones that are both disease resistant and have extra showy flowers. They can tolerate periods of dry soil and some salt runoff. Ding, ding, ding!

Compact, disease-resistant crabapple cultivars are equally useful to homeowners and city foresters.

Compact, disease-resistant crabapple cultivars are equally useful to homeowners and city foresters.

Scenario C

  • You live in USDA Hardiness Zone 6b.
  • This part of your yard is flooded in the spring, but then gets quite dry in late summer. Ergo, you need something that can tolerate extremes of soil hydrology.
  • There are no overhead wires or underground utilities in the vicinity. There is plenty of above- and below-ground space.
  • Your soil is acidic to neutral (under 7.5).
  • You like big trees, but you hate raking leaves.

A good match. You have lots of room, so why not go for something that gets really tall (60 feet or more)? RUT shows that the majestic baldcypress (Taxodium distichum) is adapted to both seasonally wet and dry soils. It is hardy to Zone 5a or better. The leaflets are tiny and need no raking. We have a match!

baldcypress grove forest lawn

Baldcypress (Taxodium distichum) tolerates extremes of wet and dry. Photo by Michelle Sutton.

Scenario D, Or, Not Every Site Can Support a Tree  

Your soil is impenetrably hard to dig in and/or bedrock is close to the surface. You could remediate a discrete area of poor soil with compost and deep tillage, but it will be expensive to create enough hospitable soil volume for tree roots, which grow well beyond the canopy. Bassuk says, “There is one site problem that we cannot select for—and that is lack of rooting space.”  Best not to plant a tree here.

Or, you’d love a weeping cherry but there is only 10 feet clearance between house and sidewalk (weeping cherry trees get much bigger than that over time). Or, you want an oak tree, but there are overhead wires in the vicinity. Find a place in your landscape where these trees will have adequate above- and below-ground room.

In terms of aerial room, RUT will tell you how big you can anticipate a tree getting. How much soil volume is adequate to support a tree of a given size? There is a terrific soil volume calculation guide on p. 20 of this UHI publication: www.hort.cornell.edu/uhi/outreach/pdfs/walk1.pdf.

More UHI Resources for Homeowners

The Cornell Woody Plants Database is another great tool for site-plant matching and includes shrubs as well as trees: http://woodyplants.cals.cornell.edu. Bassuk says a grant has been awarded to UHI that will enable the database to be upgraded soon, making it more user-friendly and field-friendly. The search function will be improved and a Cornell Woody Plants Database app for smartphones will be released.

Bassuk also wants readers to know about the community forestry resources page through the UHI site: www.hort.cornell.edu/commfor/resources/index.html. Here you can find pruning and transplanting guides, advice on how to avoid construction damage to trees, pest and disease problems, and much more practical information.

When we think about providing protective cover for slopes and other difficult sites, herbaceous groundcovers come to mind. Here is a really useful guide to deciduous woody groundcovers for such sites, borne from former graduate student Jamie Blackburn’s field testing of such underutilized plants in the city of Ithaca: www.hort.cornell.edu/uhi/outreach/pdfs/dwgc.pdf.

If you have a large enough property and are thinking about putting in a double row, or allée, of trees, instead of sinking all into a vulnerable monoculture, there is a way that you can plant a visually compatible diversity of trees; see:

www.hort.cornell.edu/uhi/outreach/pdfs/visually_compatible_trees.pdf.

Lastly, for site assessment purposes, to find out down to an “a” or “b” what your Hardiness Zone is, go to this USDA site for an interactive map:

http://planthardiness.ars.usda.gov/PHZMWeb/Images/150dpi/NY.jpg

{ 1 comment }

Google+