Garden Design

Native plants and pollinators

by cathym on May 11, 2020

by Lisa Ballantyne

Native plants are indigenous to a region. They have existed there for a very long time—have adapted perfectly to its conditions and support the local ecosystem, including important pollinators. 

Since the plants, animals and insects have co-existed for many, many years there is often a symbiotic nature. Certain plants attract certain insects. For instance, swamp milkweed, Asclepias incarnata, is a primary host plant for Monarch butterflies. Highbush blueberry is an excellent food source for mining bees, mason bees, and long-tongued bumble bees. 

Monarch caterpillar on swamp milkweed. Photo courtesy Liz Ballantyne

Interest in returning to having native plants in our yards and gardens has certainly been surging. Gardeners are looking for native trees, shrubs and perennials. Fortunately, the availability of these plants is beginning to grow with more and more choices available every year. 

As is well known, many of our native pollinators have been struggling to survive. Some believe that a lack of native plants plays a role. Much land has been cleared for housing, farming and other development. To counter this habitat loss, we are beginning to see farmers leaving wider hedgerows as an increase in pollinators means higher yields. We as homeowners and consumers can do our part by planting more native plants to support pollinators. Reducing or even eliminating lawn areas and replacing with natives can go a long way in providing food and habitat that has long been lacking. 

It is important for our native pollinators to have a food source from early spring to late fall. When adding new plants to your garden or yard try to be conscious of the need for early-, mid- and late-season flowering plants. 

EARLY BLOOMING Pussy willow. Photo courtesy Flickr: Bambe1964
MID-SEASON BLOOMING Spicebush swallowtail on wild bergamot. Photo courtesy Flickr: Candy & Kasey

Early blooming native plants include wild geranium (Geranium maculatum), pussy willow (Salix discolor), and raspberry (Rubus spp.). Mid-season natives would be plants such as wild bergamot (Monarda fistulosa), swamp milkweed (Asclepias incarnata) and American basswood (Tilia americana). Late season flowering native plants might be cardinal flower (Lobelia cardinalis), buttonbush (Cephalanthus occidentalis) and New England aster (Symphyotrichum novae-angliae). 

LATE BLOOMING New England aster. Photo by Jane Milliman

There is no question that the natural world is a complicated balance of plants, animals, insects and environmental factors such as weather. When one goes out of balance, so go the others. Often, we humans can unwittingly have a hand in throwing off that balance. Planting more native plants, can be our way of starting to put things right. 

Lisa Ballantyne is co-owner of Ballantyne Gardens in Liverpool, NY. She and husband Tim have a nursery and landscaping business that promotes organic gardening, gardening for wildlife, and native plantings. 

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by Michelle Sutton

Two good plants for the “high and dry” part of the rain garden or bioswale: goldenrod (Solidago ‘Fireworks’) and narrowleaf ironweed (Vernonia lettermannii ‘Iron Butterfly’). Photo by Michelle Sutton

MINI-GLOSSARY OF ESSENTIAL TERMS

Stormwater is the excess water from rain events and melting snow that doesn’t immediately infiltrate soil, but rather flows across the soil surface. Stormwater infrastructure is costly to municipalities, and haphazard stormwater runoff is harmful to ecosystems because of streambank erosion, excessive sedimentation, bacterial and fertilizer contamination of waterways, and more.   

Bioswales are strategically located trenches in the earth that are lined with porous materials and plants in order to slow stormwater runoff so that it can infiltrate and be cleaned by the soil. Bioswales and rain gardens are both constructed to slow water movement, but bioswales are designed to handle a specific amount of runoff from a large impervious surface, such as a roadway or parking lot. Plants in bioswales assist with stormwater infiltration and provide ecosystem services like wildlife habitat creation and urban heat island cooling. 

Rain gardens tend to be smaller than bioswales and are more commonly used for residential stormwater management. As defined by the Cornell Urban Horticulture Institute, rain gardens are “constructed vegetated depressions used to temporarily retain stormwater runoff from impervious surfaces during storm events typically of one inch or less. Using plants and distinct engineered substrates, pollutants are filtered and water infiltrates into the soil over a period of one to 2 days.” 

SMALL-SCALE STORMWATER MANAGEMENT
Jeanine “J” Fyfe is an education and design specialist at Rochester-based Broccolo Tree and Lawn Care. “Rain gardens are like all stormwater management systems,” she says. “Because they help keep our watersheds healthy, rain gardens benefit everyone.”

“Patience is needed for rain gardens, because the plants take time to establish,” Fyfe says. “While conventional drainage systems are about diverting water—and can sometimes divert water right over to the neighbor’s, creating more problems—rain gardens are about keeping water in place and allowing it to recharge the groundwater.” 

Fyfe explains how the rain garden system has to be set up properly and given time to flourish. For instance, natural fiber logs, like those filled with coir (coconut fiber) can be used to hold earth in place until plant roots are established. Shoreline and slope erosion can be controlled with natural fiber logs along with appropriate plants that hold the soil and help filter rainwater runoff.

As she does with all types of gardens, Fyfe looks at the rain garden through an ecosystem lens. Rain gardens are an opportunity to create habitat, attracting insects whose presence attracts frogs and birds. “A barren, wet area is just an invitation for mosquitos to breed, so plants are a must to house the creatures that will keep the ‘bad bugs’ in check,” Fyfe says. She prefers the use of native plants wherever possible, primarily because she regards them as the best food sources for local pollinators. She also steers clients clear of unwanted aggressive or potentially invasive plants.   

The first question Fyfe asks clients is, “In addition to stormwater management and beauty, what purpose(s) do you want your rain garden to fulfill?” This could include erosion control, privacy screening, and/or maximum wildlife appeal. Then she delves into site assessment: Is the site wet all the time, or just in spring? How dry does it get in summer? How much light does it get and during which parts of the day? What is the existing soil like, and how fast does infiltration currently occur? What other specific challenges exist? 

This assessment guides the selection of the appropriate soil amendments and plants to match the site. Starting with trees like maples (Acer spp.), willows (Salix spp.), and some oaks (Quercus spp.) that prefer moist areas, Fyfe’s selection trickles down to shrubs such as chokeberry (Aronia spp.), dogwoods (Cornus spp.), sumac (Rhus spp.) and summersweet (Clethra spp.), followed by perennials and ground covers like ferns, spiderwort (Tradescantia spp.), and lobelia (Lobelia spp.). “Grasses like tussock sedge (Carex stricta) look great massed together and can cover lots of territory, linking areas together to provide a natural, meadow-like appearance,” she says.

Plants on the upper slope or edge of rain gardens and bioswales must be drought tolerant. Photo by Michelle Sutton

• • •

One major plant selection consideration for rain gardens and bioswales is the differing microclimate in the bottom vs. the top of the system. Designers usually think in terms of the “low and moist” vs. the “high and dry” parts of the rain garden or bioswale. However, depending on the site, the whole rain garden might become quite dry in summer, which means that the plants chosen would have to tolerate both wet and dry conditions.   

If your rain garden will cover a larger area, consider incorporating woody plants. The Cornell Woody Shrubs for Stormwater Retention publication is a superb resource. As explained within: “While a wide variety of herbaceous plants such as soft rush (Juncus effusus), swamp milkweed (Asclepias incarnata), and Joe-pye weed (Eutrochium spp., formerly Eupatorium spp.) are often successfully used in these spaces, they can present maintenance issues because of the need to annually cut back dead foliage and stems. Utilizing woody plants decreases the need for additional seasonal maintenance while successfully adding aesthetic and functional vegetation to stormwater retention practices.” The publication includes dozens of research-tested suggestions for woody shrubs that can tolerate both wet and dry conditions.   

TIPS FOR A SUCCESSFUL RAIN GARDEN

• The slope of the land will determine the needed depth of the garden (see savetherain.us for the calculation).

• A two- to three-inch covering of well-aged shredded hardwood mulch helps with weed control and drainage and can give a more attractive look to the garden. Pine bark nuggets and other wood chips are not recommended because they will wash out more readily. 

• For the first few years of the rain garden, weed management is crucial until the desired plants are established and can shade out competitors.  

• At maturity, properly selected plants in the rain garden shouldn’t require supplemental water. However, mature plants may look better if watered during a drought.

• Snow can be “stored” in the rain garden so long as any woody vegetation isn’t overloaded to the point of breaking branches.  

• If the rain garden is near paved surfaces that get treated with deicing salt in winter, select salt-tolerant plants. 

KEY UPSTATE RESOURCES

Save the Rain
savetherain.us

H2O Hero Water Education Collaborative
H2Ohero.org

Rochester Museum and Science Center-Green Infrastructure
rmsc.org

The Cornell Botanic Gardens Bioswale in fall, 2012. Photo by Chris Kitchen Photography and Design (ckpad.co)
Interpretative signage for the bioswale. Photo by Michelle Sutton
Designer rendering of the bioswale.
A glimpse into the luxuriant center of the Cornell Botanic Gardens Bioswale in fall, 2018. Photo by Michelle Sutton
The Cornell Botanic Gardens Bioswale in late summer, 2012. Photo by Chris Kitchen Photography and Design (ckpad.co)

THE ULTIMATE BIOSWALE
Completed in 2010, the bioswale at Cornell Botanic Gardens is, like all things at this central New York public garden, horticulture at its highest level. The stunning bioswale was designed and engineered to slow and filter runoff from the adjacent Nevin Welcome Center parking lot. The plants in the bioswale are bound to be of interest to homeowners as they design their rain gardens.

  • Plants in the Cornell Botanic Gardens bioswale were chosen for strong root systems and the ability to withstand both wet and dry conditions. 
  • Most of the plants in the bioswale are native to the central New York region. Seven cultivars of native switchgrass (Panicum virgatum) are used, and about 68 different flowering perennials add color, pollinator value, and wildlife habitat. These perennials include showy goldenrods like Solidago ‘Fireworks’, narrowleaf ironweed (Vernonia lettermannii ‘Iron Butterfly’), and various cultivars of sneezeweed (Helenium spp.), coneflowers (Echinacea spp.), and false indigo (Baptisia spp.). 
  • The bioswale mitigates stormwater runoff to nearby Beebe Lake, protecting the lake from storm surges and erosion. 
  • To increase the rate of infiltration, the bioswale soil is a one-to-one-to-one ratio mix of coarse sand, screened loam, and Cornell compost. 
  • In a 2015 study, Cornell researchers Palmer and Powell found that the bioswale was reducing peak stormwater flow rates by 81% and reducing runoff by 31% (78,000 gallons annually). 
  • As water infiltrates through the bioswale, sediment and pollutants are filtered out. Soil and root microorganisms help break down harmful bacteria and trap heavy metals along with excessive nitrogen and phosphorus. The bioswale has been shown to remove 80% of the average annual total suspended solids (dry weight of suspended particles).

Michelle Sutton (michellejudysutton.com) is a horticulturist, writer, and editor living in New Paltz.

Special thank you to Ithaca-based Chris Kitchen for use of his Cornell Botanic Gardens Bioswale photos. Contact info: 

Chris Kitchen Photography and Design
facebook.com/ckpad
ckpad.co
(607) 280-9573 

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story and photos by Christine Froehlich

Shrubs of varying heights create interest and privacy

Bumping up curb appeal often starts with buying more plants. A few shrubs, a tree, or some snazzy containers might be just the thing… or is it? A quick fix can be tempting, but if you want to improve the looks of your front yard and you aren’t sure how to get started, adding more plants right off the bat might not be the answer. Sometimes the best way go about it is to work with what you already have. You might even end up liking the plants you think you want to get rid of.

An autumn view of the garden

Robert Salmon and Catherine Fuller’s garden makeover began with a bunch of spindly trees in their front yard. Robert had been eying the forlorn specimens, worried they might fall on the house. He was about to carefully go at them with a chain saw when his wife, Catherine, called me to consult about their fate—and general appearance of the front yard. She was afraid that if they were removed their house would be too exposed to the street. 

The trees, an assortment of self-sown cherry trees (with a few nice oak and ash saplings mixed in) were leggy specimens with no great appeal. But on the plus side, they provided a degree of privacy from the road and connected the house with the woodlands surrounding it. We decided to compromise on the trees, selecting the healthiest ones with the nicest forms and removing the rest. Even though they weren’t perfect specimens, their height offset the scale of the two-story house. Plus, they would provide a perfect canopy for more attractive plants—a layered planting of shrubs and possibly perennials or groundcovers. We began brainstorming about how to marry it all up to the existing woodlands and foundation plantings that hugged the house.

View from the street
Planted areas seamlessly blend with surrounding landscape

The trees sprang up randomly from an enormous oval shaped bed about fifteen feet from the house and spanned almost the entire width of the front yard. It was a natural but sloppy mess filled with weeds and junky shrubs, but strengthening the connection between the existing foundation plantings and woodlands with better looking plants had possibilities. 

It was a lot of space to plant. Robert and Catherine both like to garden, but their busy work schedules limited gardening, so we needed to make it as low-maintenance as possible. 

Getting Started
We chose plants that would help integrate the leggy trees into the surrounding landscape. Robert and Catherine had a lot of room to work with and their house was large. If your property is small, take heart—the same concept can be used with smaller-scale plants.

Begin by choosing varieties with cultural needs that suit your site and fit the style you want. The growth habit and mature size of the plants you choose should match up to the job you want them to do. For example, slow-growing shrubs or trees with a vertical habit for tight spaces, fast-growing flowering shrubs for privacy borders, or plants with distinct forms to serve as focal points. 

Add Structure
We began with structural plants—the trees and shrubs. The largest specimens went in first. To balance the scale of the existing trees and insure against future tree loss, we planted Fagus sylvatica ‘Asplenifolia’ on the opposite side of the bed. Commonly known as fern-leaf beech, this stately tree has a pyramidal shape and a lovely texture—the delicate cut leaf resembles fern foliage. 

Around the base of the leggy trees, a mass of Viburnum tomentosum took care of masking the bare bottoms. Also known as doublefile viburnum, you can’t beat it for quick coverage. This fast-growing, deciduous shrub is tall (twelve to fifteen feet) and has a horizontal branching habit (eight to ten feet wide) that makes an attractive screen. Outrageous clusters of white flowers blossom from late May through June, and in fall, the leaves turn an intense plum color with red fruits the birds flock to.

Form and Foliage 
The form of the shrubs and trees dictate the style of a planting. Here, they played an important role in contributing to what I call “the controlled wild look.” The idea was to mimic the woodland without looking sloppy. Fast-growing deciduous shrubs with relaxed growth habits fit the bill. 

We bumped up curb appeal by choosing shrubs with exciting foliage, flowers, berries and interesting texture.

Layers of Shrubs
Shrubs of varying heights were layered together in groups of three and five throughout the bed. This lent a naturalistic look to the planting and provided more screening from the street. 

Many deciduous shrubs of varying sizes offer gold, magenta and variegated foliage. Most are fast growing and are an inexpensive way to fill space quickly and attractively. We made the most of their attributes here, contrasting foliage colors to increase visual impact. 

What We Planted And Why
Most of the shrubs used are deciduous, but some evergreens were included for additional winter interest.

Physocarpus opulifolius ‘Diabolo’ (ninebark) has an arching habit that resembles forsythia and sports pretty, whitish-pink flowers in June. I like it best for the wine-colored foliage that pops out in late spring. Unpruned, this shrub matures at around eight to ten feet tall with a spread of six to eight feet, perfect for the back of the bed.

Cornus alba ‘Ivory Halo’ (Red twig dogwood) The flowers aren’t showy, but the crisp green and white leaves are striking. It grows quickly (four to five feet) and has bright red bark that adds color to a winter landscape.

Ilex meservae ‘Blue Girl’ and ‘Blue Boy’ are also known as blue holly because of their dark blue-green leaves. This variety grows a little slower than others, usually about five to six feet depending on conditions. Red berries and shiny dark leaves add contrast and winter color. Hollies come in two sexes and only females produce berries. To get them to berry you need to have a boy nearby, so make sure to plant both.

Weigela florida ‘Wine and Roses’ The combination of the dark magenta leaf and vibrant pink flowers make this one of my favorite mid-sized shrubs. It reaches a height of about 4 feet and has an arching growth habit.

Hydrangea quercifolia‘Snowflake’: Also known as Oakleaf hydrangea, this slower-growing variety is five to six feet tall. Longwhite panicles pop out in August and turn pink as fall arrives. Bold leaves, which are shaped like oak leaves (hence the name) turn deep magenta as fall progresses.

No Bare Ground
It takes around three years for shrubs to mature. While you’re waiting for them to grow, the quickest way to reduce weeding and achieve immediate gratification is to fill in bare spots with perennials. Obviously, you don’t want any you’ll have to stake or deadhead, so pick low maintenance varieties.

For this planting we chose varieties with interesting foliage and long-lasting flowers. 

HostaSum and Substance’: This big hosta (about 3 ½ ft tall) adds pizazz to a shady garden with its enormous pleated chartreuse leaves.

Nepeta ‘Six Hills Giant’: Nepeta, especially this cultivar, (36” tall and wide) tends to hog all the space around it, but there was plenty of room here. The long-lasting blue flowers and gray foliage provided a tidy border for the front of the bed.

Amsonia hubrichtii: Commonly known as Bluestar, the pale blue flowers that bloom in June and July are pretty, but I chose this substantial (2’x3’) perennial for the delicate feathery foliage that turns vibrant gold in early fall.

Calamagrostis × acutiflora ‘Karl Foester’: Also known as feather reed grass, this tall (4’) upright grass has attractive vertical foliage that doesn’t flop. It looks pretty in winter too.

Pennisetum alopecuroides: A fat fuzzy grass around 3 ½ feet tall great for added softness and height.

Several views of the mix of trees, shrubs,
and perennials in the Salmon-Fuller garden

By the end of the first summer, the bottoms of the leggy trees were almost hidden by shrub foliage, and the bed blended gracefully into the foundation plantings and natural stone wall Robert had built. It was a perfect marriage.  Robert and Catherine liked it so much that they kept on going, eventually reclaiming more of their overgrown property and extending the controlled wild look farther out into the woods. 

While we all might not be able to turn an ugly duckling into a swan, most of us have plantings that could be rearranged, or embellished to increase curb appeal. It’s worth taking a closer look at what’s going on in the front yard before you go shopping. Who knows? You might end up creating a garden you really want instead of the one you think you’re stuck with. 

View from the front door to the street

Find Christine Froehlich at gardeningwithwhatyouhave.com.

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