Low maintenance plantings are in vogue these days. As homeowners' lives become more and more hectic, the desire to plant trees and shrubs that require minimal care is increased. Fortunately, there are many available ornamentals that are not troubled by a huge pest complex, and that do appear pleasing with little care. However, a little planning in advance is still necessary for developing an attractive planting that is likely to last for many years. Even the easiest-to-care-for ornamentals still have basic needs that must be met before they will thrive. Therefore, matching the site limitations or opportunities to the plants' requirements will go far toward achieving "low maintenance" status. Before you can make the best choice, you need to assess your site, both above and below ground.
The following information will help you to assess your site before choosing the best plants for the location you have in mind. Examples of plants are given, but the resources at the end will provide you with more in-depth lists of recommended ornamentals.
Restricted Rooting Space.
Are there underground obstacles to consider? Do you see noticeable compaction near driveways and sidewalks? This potential restriction of the rooting zone very much limits the amount of water, nutrients, and oxygen available to the plant. The addition of organic matter will provide more suitable soil conditions for growing annuals and perennials. Drought tolerant trees such as Japanese Tree Lilac (Syringa reticulata) do reasonably well in compacted soils. However, since roots typically grow no deeper than three feet and can spread to two or three times beyond the dripline, a large space should be allowed before planting.
What is the texture of your soil? Is it light, dry and sandy, or is it a heavy, clay soil that tends to take a long time to drain? Perhaps you're fortunate, and have a well-drained loamy soil. This important piece of information will help you to select ornamentals that are well-adapted to your soil conditions. While some are tolerant of a wide range of conditions, others perform best in more specific locations. For example, the American Hornbeam (Carpinus caroliniana) is a small tree worthy of planting, and although it will tolerate some intermittent drought, it prefers moist, shaded soils.
The pH is a measure of how acid or alkaline the soil is; a simple pH test can determine your site's characteristics. Most urban soils have a high pH (nearer to neutral or more alkaline in nature) due to the limestone containing materials in the street environment; rural and suburban soils vary greatly throughout the state. The Hedge Maple (Acer campestre), Thornless Hawthorn 'Ohio Pioneer' (Crataegus punctata inermis 'Ohio Pioneer') and Swedish Mountain Ash (Sorbus intermedia) are all examples of low maintenance small trees that will tolerate a high pH soil. Tallhedge (Rhamnus frangula) is an upright shrub that will tolerate alkaline soil.
Poor drainage due to compaction, underground obstacles, or the inherent nature of the soil can easily be determined before you make the wrong selection. Place an open-ended coffee can where you want to plant; pour water in and observe the time it takes to drain. If the water hasn't drained at least one inch in an hour, you may want to modify the drainage in the area by using raised beds or supplemental drains, or choose species that can tolerate "wet feet." The London Planetree (Platanus x acerifolia) is an example of a tall (70-100 ft.) tree which can tolerate either wet or dry soil. Astilbe (Astilbe species) is a perennial that will tolerate moist sites.
Road Salt. Many homeowners are unpleasantly surprised to discover that some of their favorite roadside trees, such as the Sugar Maple (Acer saccharum) and Red Maple (A. rubrum) are actually very sensitive to salt injury. On the other hand, Honeylocust (Gleditsia triacanthos) and Callery Pear (Pyrus calleryana) can tolerate salt. In an area of high road salt or sidewalk salt applications, appropriate species can be planted to minimize damage later on.
USDA Hardiness Zones. All trees chosen for your planting should be cold hardy. Areas near large lakes and oceans (e.g., the Finger Lakes, Ontario, Erie, Long Island) tend to be somewhat buffered from severe temperatures, while urban environments often fluctuate more in temperature due to heat from buildings. Buildings in cities often provide some shelter from drying winds; plants in containers are more susceptible to cold winter temperatures than those in the ground. If this seems confusing, a good rule of thumb is to choose plants that conform to your zone or lower (colder temperatures). There is a USDA Hardiness zone map in the Recommended Urban Trees publication listed in the resource section.
Exposure. Take a close look at how much exposure to wind your site receives. Is it protected from winds? Excessively windy sites will often place stress on plants with large leaves, which leads to unsightly leaf tatter. Also, plants in these sites may need supplemental watering so they do not dry out as quickly. Hackberry (Celtis occidentalis) is a medium to large tree which is quite wind resistant.
Think about exposure to light as well. Shady sites determined by the sun and shade patterns around buildings, as well as nearby trees, may limit the choice of plants. Most trees and shrubs require full sun, but a few such as Katsura Tree (Cercidiphyllum japonicum) tolerate partial shade. Bleeding Heart (Dicentra species) is a perennial that will do well in partial shade.
Building Set-Back, Overhead Wires. The presence of physical barriers to plant growth above ground, such as a narrow building set back from the street and/or overhead wires, requires the choice of a tree or shrub which will not interfere with these structures. Columnar trees or those with low mature heights (less that 30 feet) can be used in these situations. There are many small trees and shrubs to choose from (see resource list at the end of this fact sheet); an example of a columnar tree is Princeton Sentry Ginkgo (Ginkgo biloba 'Princeton Sentry').
Surfaces that Surround Buildings. Concrete, asphalt, car tops, mirrored building surfaces, etc., increase the reflected and irradiated heat load on a tree, which can cause it to heat up and lose water from its leaves at a faster rate than normal. Drought resistant plants should always be selected in those circumstances. A good example of a drought tolerant tree is the Yellow Chestnut Oak (Quercus muehlenbergii). Coneflower (Rudbeckia speciosa) is a perennial that will tolerate dry, hot conditions.
Bassuk, Nina L. Recommended Urban Trees. Urban Horticulture Institute, 20 Plant Science Building, Cornell University, Ithaca, NY. Cost: $8.00. Ordering information. | Online version
Dirr, M. Fourth Edition, 1990. Manual of Woody Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Champaign, Illinois: Stipes Publishing Company.
Gerhold, H.D., W.N. Wandell, N.L. Lacasse, and R.D. Schein. 1989. Street Tree Fact Sheets. Municipal Tree Restoration Program of Forest Resources, The Pennsylvania State University, University Park, PA 16802.
Harrison, F. 1983. Landscape Plants for Eastern North America. New York: John Wiley and Sons, Inc.
Still, Steven M. 1982/1994. Herbaceous Ornamental Plants. Champaign, Illinois: Stipes Publishing Company.
Van Gelderson, D.M. and J.R.P. Van Hoey Smith. Second Edition, 1989. Conifers. Portland, Oregon: Timber Press, Inc.
Wyman, D. 1969. Shrubs and Vines for American Gardens. New York, NY: Macmillan Publishing Company.
Wyman, D. Trees for American Gardens. Third Edition, 1990. New York, NY: Macmillan Publishing Company.
Cornell Cooperative Extension Publications
Shrubs for Landscape Plantings in New York State - 141IB50
Ornamental Grasses for the Home and Garden - 141IB64
Annual Flowers for N.Y.S. - 141IB93
Sequence of Bloom of Perennials, Biennials, and Bulbs
Reducing Deer Damage to Home Garden Plantings
Dr. Nina Bassuk, Urban Horticulture Institute, Cornell University, Ithaca, NY.
Marcia Eames-Sheavly, Department of Fruit and Vegetable Science, Cornell University, Ithaca, NY.
Robert Kozlowski, Department of Floriculture and Ornamental Horticulture, Cornell University, Ithaca, NY.