Selecting Trees and Shrubs for Our Climate
by Neil Soderstrom
Besides beauty, trees and shrubs can contribute significantly to your house's property value—without increasing property taxes. They are an investment that grows in aesthetic and dollar value every year, while potentially reducing lawn work and related costs. Trees and shrubs can also reduce your cooling and heating bills by providing shade in summer and windbreaks in winter. And if these plants suffer storm damage, you might be able to obtain insurance settlements and take income tax deductions.
In addition, trees and shrubs supply oxygen to the Hudson Valley, absorb air pollutants, reduce noise pollution, and sequester carbon dioxide, a gas that continues to hasten global warming.
Tree vs. Shrub
The terms tree and shrub can at times seem arbitrary because there are treelike shrubs and shrublike trees, both in nature and in cultivated varieties. Yet the terms generally help in visualizing distinctions. Although trees and shrubs have hard woody stems that increase in girth annually, trees tend to develop one main trunk or just a few trunks from the same base, as birches do. Instead, a shrub develops numerous stems from the same base and remains less than twenty feet tall. So, even though short trees remain shorter than tall shrubs, their trunks distinguish them.
Plant Prices
You can buy two- to three-year-old bare-root seedlings and young transplants for as little as $1 or $2 each, whether locally from organizations that promote woody plants or through mail order. For $10 to $50 each at garden centers, you can buy young trees and shrubs with roots well established in soil containers. For $50 to $1,000 or more, you can buy older trees and shrubs with heavy root balls wrapped in burlap. Depending on unit cost and quantity, a nursery may agree to plant for free. But if they do the planting, insist on a year's warranty.
Is bigger better? Even though large costly plants might appear to promise quicker gratification, they might not be better buys because of a phenomenon sometimes termed transplant shock, which they may suffer for several years while their cut-back roots regain their former mass and vigor. Smaller plants with a higher percentage of their original root mass can often catch up with and surpass the growth of their larger brethren in a few years.
Selection Criteria
Like clothes shopping, shopping for trees and shrubs is a trade-off between personal taste (color, style, features) and practical considerations (size, durability, suitability for climate). Although clothes may be suitable for just one season, trees and shrubs need to be suitable in all four. Also, unlike clothes, trees and shrubs can improve in appearance and value each year, but only if placed in conditions they like.
It's smart to postpone selection and planting until you've had a year or so to evaluate your planting sites in all seasons. On newly owned property, especially, wait a full year before moving existing plants. During the wait you might discover that certain drab summer "bushes" outside your living room window display striking fall color and gorgeous, fragrant spring flowers.
Growing Conditions
It's fairly easy to determine your growing conditions. The least alterable condition is your climate's temperature range, especially summer highs and winter lows. Yet even temperature can be moderated by a "microclimate" created by buildings and stonework that may serve as heat sinks and wind screens. Other vital conditions include sunlight, soil, soil acidity, precipitation, and drainage.
Sunlight. Note how the sun's daily path and its high angle in summer and lower angle in spring and fall affect sunlight and shade. You might find it helpful to record seasonal sunlight patterns in a logbook or on a property drawing. With that record, you can match new plants to your planting sites, based on published sunlight preferences of each tree and shrub usually expressed as Full Sun (6 or more hours direct sun); Partial Sun (4-6 hours), Light or Dappled Shade (sunlight through sparse foliage); Shade (no direct sun, as found on the north side of buildings).
Cold Hardiness. Before selecting a plant, you need to know whether it can survive our winters. Rhinebeck is in Cold Hardiness Zone 5, meaning that the average coldest winter temparatures may be as cold as -20° to -10° F. Much of New York City, by comparison, is in Cold Hardiness Zone 7, in which average coldest temperatures may be considerably warmer, perhaps never dropping below 10° F. The zone numbers are only rough guides for our region, not necessarily for your property. For example, cold air settles at night into low pockets, where temperatures may be 5° to 10° F colder than on nearby hillsides. Also, wind chill can make conditions seem far colder than the thermometer indicates.
Heat Hardiness. In the late 1990s, the American Horticultural Society introduced its Heat Zone Map. Its zones indicate the average annual number of days that exceed 86° F. As field tests of plants catch up with the Heat Zone system, commercial growers will increasingly publish pairs of hardiness numbers—one for cold tolerance, one for heat. For now though, if you lack the heat hardiness number for a given plant, it's prudent to give summer's dog days a thought. "East Coast native plants do well in our region," suggests Norbert Lazar, owner/operator of the Phantom Gardener, located between Rhinebeck and Red Hook on Route 9. Norbert recommends "native beauties, such as blueberry, bayberry, inkberry, witch-hazel, fothergilla, and itea," among many others. He adds "these natives add multi-seasonal aesthetic interest close to the house and to other important viewing areas."
Soil. Given appropriate climate and sunlight, plants fail more often from inappropriate soil than any other cause. Of course, you could take a chance and simply select plants that tolerate a wide range of soils. But you'll have better results if you select plants that you're sure are suitable for your soil. Key considerations are soil acidity and soil texture (whether predominantly clay, sand, or loam).
Relative acidity determines how well plants can utilize water-soluble soil nutrients. Each plant has its own range of pH preferences, a pH range in which the nutrients it needs are available. Most trees and shrubs thrive in slightly acid soils, those with pH of 5.5 to 6.8. (A pH of 7.0 is considered neutral.) Some plants, such as rhododendrons and certain oaks, prefer especially acid soils of 4.5 to 5.5. Others such as apples, boxwoods, and junipers prefer neutral soils of 6.5 to 7.5. But rather than battling extreme soil pH by applying lime to sweeten acidity or sulfur to reduce alkalinity, you'll have long-term better results with plants that like the pH where you planted them.
You can conduct rough pH tests inexpensively by using either an electronic meter or a simple soil-testing kit with color-matching chart. However, for a more complete analysis, especially if you plan to invest in costly plants, it's wise to submit soil samples to the Cornell Cooperative Extension in Millbook (845-677-8223), which performs simpler tests and forwards soil for the more complex tests to Cornell. In addition to pH, a lab analysis will tell you whether the soil is deficient in any major or minor minerals. Basic tests run $7 to $15 or so. Elaborate tests, including tests for heavy metals (recommended if you plan to grow fruit trees and vegetables) can run $100 or more.
Although the US Department of Agriculture publishes soil maps (indicating soil types), the map for your locale may not apply to your site if the developer hauled off your topsoil. Or the developer may have imported fill or dumped clay from basement excavation where you plan to plant.
Drainage is another crucial concern. Although all plants need moist soil to make minerals soluble for uptake by their roots, the roots can literally drown (suffocate) if the soil remains too wet for too long. For best utilization of moisture, roots need well-aerated soil—soil that is porous enough for water to drain away yet absorbent enough to retain moisture. Ideal porosity literally lets roots breathe and conduct gas exchanges with underground air. If aeration is poor, roots may grow too shallowly, near the surface where they find it easier to breathe. Shallow root systems are more susceptible to drought and don't adequately anchor trees and shrubs in wind. If your soil doesn't drain well, you'll need to improve drainage by installing drain tubing or tiles, or else use plants that like "wet feet," such as willows and bald cypress.
Compost can improve soil aeration in clayey soils. Still, latest research suggests that woody plants fare better when planting holes are backfilled with unamended original soil. Over time, however, it's helpful to use compost and wood chips as a top dressing, or mulch, as we'll discuss in the Fall issue of AboutTown, on planting trees and shrubs.
Design Options
There's no need to install a fully designed garden all at once. Patience hath its rewards. You can begin gradually by selecting just a few trees and shrubs each year, and supplementing as time and budget allow. Unlike fall-planted narcissus and tulip bulbs that provide stunning displays the next spring, young trees and shrubs need years before beginning to show their mature form and sending forth flower and fruit. Even the bark of a tree celebrated for its winter beauty won't begin to impress until the trunk gains some girth.
As to design, there are whole books by and about landscape designers who are truly artists with form, color, and texture. If you have a flair for drawing and painting, you'll have an advantage in visualizing and sketching design combinations. Yet many excellent garden designers can't draw worth a hoot, but know plants, and can visualize how they'll look five and ten years out—through all seasons.
Knowing little about trees and shrubs, many people settle for the year-round green of juniper hedges and a spring-blooming rhododendron or two, and simply mow the rest. But your options between that and hiring a costly design firm are many, requiring varying amounts of research and commitment.
Some of the better books on design and selection are listed below. The best books for this purpose profile hundreds of trees and shrubs, addressing the full range of North American growing conditions. Yet although photos and descriptions can be valuable, they're not as valuable as seeing the plants themselves.
For this, consider visiting public gardens and arboreta in our region, such as Innisfree Garden and the Institute of Ecosystems Studies, both located in Millbrook. They feature stunning tree and shrub combinations, often in association with nonwoody plants. There too you'll have a chance of obtaining free brochures on the plants and perhaps encountering garden staff willing to discuss their plants and offer suggestions for your situation.
Also visit local nurseries and garden centers. They usually offer design consultations that may be free or at nominal cost if you purchase their plants. Phantom Gardener's Norbert Lazar advises that many people mistakenly ask for plants that look good only in one season, such as lilacs. He especially warns against planting "invasive exotics, such as Japanese barberry, Russian olives, and burning bush, which can spread rapidly and choke out nearby natives." He will present a workshop on ornamental shrubs at Phantom Gardener on Sunday, March 9th, at 10:00 and offers other Sunday workshops throughout spring: (845) 876-8606.
Grandiflora's Katie Buderus says that they do not offer formal workshops, but will demonstrate gardening techiques at the store or give lessons at home. And Ruth Green of Clinton Hollow Herbs, though hesitant to label any of her herbal plants shrubs — other than perhaps lavender and vanilla tree — also offers home consultations.
Roots & Branches
You may have heard the joke about the dentist who commented to a young patient, "Your teeth look great, kid, but your gums have to go." Such dark humor can apply to young trees and shrubs that look good but have damaged or otherwise troubled root systems.
In a nursery, trees and shrubs with roots in containers and those that are balled-and-burlapped (B&B) can look good for a year or more if watered well. The key here is size of the root mass in relation to plant size. Under natural growing conditions, tree and shrub roots will have approximately the same mass below ground as aboveground. Most root systems grow near the surface, usually spreading well beyond the drip line of outermost branches. If young seedlings are carefully repotted into increasingly spacious pots as they grow, with all roots intact, the roots will absorb water and nutrients better than rootballs of B&B plants that typically have only 10-15 percent of their original root systems intact.
In your aboveground inspection, favor healthy looking plants with stout twigs, suggesting good reserves of carbohydrates needed for resumed growth upon planting. Noted horticulturist and author Lee Reich, from New Paltz, prefers plants no more than 1-1/2 times taller than their container. Avoid plants with withered or diseased branches or leaves. Then try to determine how the roots are doing. For this, slip a container plant out of its container to ensure it isn't rootbound—with roots cramped in a spaghetti-like mass. You can often spot rootbound container plants from a distance because their roots often protrude from container drain holes. Balled-and-burlapped plants should have substantial, firmly wrapped rootballs with no sagging burlap, suggesting that air pockets have allowed roots to dry there.
You'll find more tips on root inspection in the fall issue of AboutTown, when we'll address the planting of trees and shrubs.
Neil Soderstrom is a gardening writer and photographer based in Wingdale, NY, also found at www.agpix.com/soderstrom.
*Paintings above are by Michele Angle Farrar, reprinted from Trees, Shrubs & Hedges for Home Landscaping by Jacqueline Hériteau ($19.95 from www.creativehomeowner.com).
Recommended Reading
Complete Book of Shrubs by Kim Tripp & Allen Coombes (Reader's Digest, 1998).
Dirr's Hardy Trees and Shrubs by Michael Dirr (Timber Press, 1997)
Home Landscaping--a series of six books by Roger Holmes, Rita Buchanan, and others, each devoted to a distinct region: Northeastern U.S. & Southern Canada (Creative Homeowner, phone: 1-800-631-7795, ext. 320)
Trees, Shrubs & Hedges for Home Landscaping by Jacqueline Hériteau (Creative Homeowner, 1999, phone: 1-800-631-7795, ext. 320)
Local Garden Centers, Garden Designers
Adams Fairacre Farms: Route 9W Kingston (845) 336-6300; Route 44 Poughkeepsie (845) 454-4330; Route 300, Newburgh (845) 569-0303
Clinton Hollow Herbs, 638 Fiddlers Bridge Rd., Clinton Corners, (845) 266-5202
Grandiflora, 144 Pitcher Lane, Red Hook,(845) 758-2020
Howard's Agway, Salt Point Rd., Clinton Corners, (845) 266-3494
Mac's Farm & Garden Shop, 68 Firehouse Lane, Red Hook, (845) 876-1559
Eve Minson Land Design & Planning, 452 Church Rd., Hudson, NY 12534, (518) 851-6604
Northern Dutchess Botanical Gardens,389 Salisbury Tpk., Rhinebeck, (845) 876-2953
Phantom Gardener, 6837 Route 9, Rhinebeck (845-876-8606)
Rockcrest Gardens, Salt Point Turnpike, Clinton Corners, (845) 266-5203
Stagia's Farm & Farm Market, Route 9, Upper Red Hook, (845) 758-6722
Thunderoc Farms Nursery, Route 9, Clermont, (518) 537-4686
Twin Ponds Nursery Garden Design, Rhinebeck, (845) 876-7476
Wonderland, East Market St., Rhinebeck, (845) 876-4981
