Natives and Cultivars
Many choices for planting trees
There is a growing trend for using naturally occurring, “native,” trees and shrubs for landscape and conservation plantings. “Native” refers to plants that naturally occurred in this area prior to European settlement. In contrast, other commercially available plants can either be “cultivars,” cultivated plants that are reproduced using cuttings or buds that are grafted onto separate root stock; or “nonnative,” plants that were not part of the landscape prior to European settlement. Each of these has its benefits and drawbacks for the homeowner to consider.
Native plants have the advantage of having been present on the landscape for thousands of years. They have coexisted with the other native fauna and flora, and they are well-suited to the local soils, climate, and environmental conditions. Planting native species creates a natural, sustainable landscape which offers more beneficial food and cover for birds, butterflies, and other wildlife. The drawbacks of native plants include decreased resistance to the nonnative insects and diseases that are now part of the landscape. The dogwood borer that attacks flowering dogwood, emerald ash borer, and Dutch elm disease are a few examples. Native plants may also be less able to tolerate the harsh growing conditions found in many urban areas, and their flowering and fruiting characteristics that make them highly desirable may be compromised in these environments.
Cultivated plants, or cultivars, have been developed to perpetuate desirable characteristics of a particular plant, including a striking flowering display (pink dogwood), fruit production, disease resistance, tree conformation (e.g. weeping cherry,) or fall color. Cultivars offer predictability, so using them helps ensure desirable attributes. So, if the intention is to create a small apple orchard, one might be more successful using cultivars that have natural resistance to diseases such as apple scab, cedar apple rust, or fire blight; have smaller stout growth habits like a dwarf tree; and are noted for abundant apple production versus planting apples grown from a native seed source. Most cultivars do not reproduce, but an exception is the Bradford pear, a cultivar that has become an invasive menace in forested communities.
Non native trees have been brought to this country ever since the arrival of the first colonists. Some of these plants have become very important parts of the landscape, such as little leaf linden or Kousa dogwood, while others have become very undesirable invasive pests, like the ailanthus tree or Norway maple. Non native trees can be useful when the native variety is not well adapted for the site. Examples of this might be using a Chinese chestnut to cultivate chestnuts instead of an American chestnut, or employing the Chinese elm instead of the Native American elm on a landscape where Dutch elm disease is a concern. In some cases, the use of cultivars or non native trees will simplify the maintenance requirements of a landscape, since these plants can have resistance to insects and diseases, or they have growth characteristics that would enable them to fit in their intended growth space without the need for corrective pruning.
If you are thinking of planting trees in an area, some good advice is to first analyze the site. How much growing space do you have? Is the site dry, wet, or in-between? Is the site sunny, or will the tree be growing in partial or full shade. What kind of soil do you have? Is it sandy and well-drained or clay and poorly drained? Is the soil loamy and well-aerated or has is it hard and compacted due to heavy foot traffic? Once you have determined these site conditions, then you can decide if a native tree will suit your needs. If not, then the use of a cultivar or nonnative tree might offer a better alternative.
Nature Note for 7/23/2017