When we moved into our house, a forester friend gave us two sprouted red oak acorns for our yard as a housewarming gift. Since our property is a big hill and was originally an old cornfield, the acorns were met with excitement, even though we knew it would take quite a few years before they provided shade. Today, those oaks are majestic and beautiful, and although planted at the same time and not too far apart, they did not grow as mirror images. What factors affect a tree and influence its growth?
Sunlight is an important consideration in choosing a tree. In our case, one of the red oaks hasn’t received the same level of sunlight. An existing maple tree’s canopy has expanded over the years to partially shade this oak, which is smaller in diameter and is growing at a slight angle, away from the maple in an effort to capture more sunlight. Pawpaw and sugar maple are two trees that can tolerate light, moderate, and full shade. There are plenty of trees and shrubs that can handle a few hours of direct sunlight or dappled sunlight such as flowering dogwood, eastern redbud, bottlebrush buckeye and American beech.
Soil drainage is a less obvious factor that influences tree growth. Many trees, white pine being one of them, cannot stand “wet feet.” Adding soil amendments in an effort to improve drainage is usually ineffective, given how far a tree’s roots may extend in width and depth from its trunk. Matching the tree species to the wet conditions will produce a healthier specimen that requires less maintenance throughout its life. Trees and shrubs that can prevail in poorly drained locations are bald cypress, dawn redwood, silky dogwood, spicebush, buttonbush, river birch and American sycamore.
Slope can affect tree growth. Slopes that face south and west tend to be drier because they face the sun, so drought resistant species will do best. In addition, slopes that have suffered erosion, because the valuable topsoil and organic matter have been washed or blown away, can be problematic. Eroded soil is oftentimes coarser with more sand and gravel, denser, shallow to bedrock, or has a high clay content – all of which impact tree growth and health. Ninebark, sassafras, hackberry, Kentucky coffeetree, staghorn or smooth sumac, Eastern red cedar, and bur oak are trees that are forgiving of less than perfect conditions.
Winter salt use can really negatively impact trees and shrubs. A few that can survive the harsh salt spray thrown by snowplows and shovels are American holly, sweetgum, ginkgo, American beautyberry, larch and persimmon. To boost tree health, consider the various ice-melt alternatives and practice S.A.L.T.: the right Stuff, the right Amount, the right Location, and the right Time.
Many people assume that spring is the perfect time to plant trees because they have an entire growing season to become established. The past few years have shown that spring can be fickle with late snows or excessive rainfall, stressful conditions for a new tree or shrub. A hot, dry summer is punishing to new trees and shrubs as well. If you can plan for about six weeks of above freezing temperatures after planting, then consider fall as an option for some species. The exception is that bareroot seedlings should always be planted in the spring, never in the fall.
Two websites that explain the benefits are https://arbordayblog.org/treeplanting/why-its-great-to-plant-trees-in-the-fall/ and https://extension.unh.edu/blog/2019/08/fall-good-time-plant-trees-shrubs.
A few more tips for success:
• A ring of mulch two to three inches deep around the tree or shrub keeps weeds and grasses from competing for water and nutrients. Do not “volcano mulch,” where mulch is piled deeply at the trunk, touching the trunk. The hazards of over- mulching are detailed in a New Jersey Agricultural Experiment Station publication at https://njaes.rutgers.edu/fs099/.
• Go native! Native species are better suited to Ohio weather which means they generally establish more quickly and will be naturally hardy and healthy. Natives have co-evolved with our native wildlife to provide excellent food, shelter and nesting sites.
• Do some research before you shop. Know the scientific name of the tree or shrub you wish to purchase so you are certain to buy exactly what you want. You can learn about many of Ohio’s common trees and shrubs and view photos of buds, bark, flowers, and more at https://forestry.ohiodnr.gov.
• Very carefully appraise the tree or shrub you wish to purchase. “A Guide to Buying Healthy Trees,” can be found at https://hortnews.extension.iastate.edu/1993/4-14-1993/trees.html. Avoid any that shows signs of stress as those often do not make it through the winter.
Investing in trees and shrubs provides beauty, oxygen, wildlife habitat, and shade to our communities. They also mitigate the effects of storms, control erosion, and remove pollutants from the atmosphere. Well-chosen and well-planted trees and shrubs add to property values and give years of enjoyment.
Check out the latest conservation information at Delaware Soil and Water Conservation District’s website and on Facebook.
Bonnie Dailey is deputy director of the Delaware Soil & Water Conservation District. For information, go to https://soilandwater.co.delaware.oh.us/.