Our thanks to Ann Farnham of the Ewing Environmental Commission for sharing this article with us about our continued use of non-native plants in the landscape.
We continue to hammer away on the disadvantages of using non-native plants. Remember, a good definition of a native plant is one that existed in any specific region before the European settlement in this country. Ewing is in the Mid-Atlantic region and our natives are well adapted to our particular soils, precipitation, temperatures, elevations and exposures. Our native wildlife – insects, mammals, birds, reptiles – developed along with them.
Many people believe that if a plant is sold at a local nursery or garden center that it is all right to use. Unfortunately, that is not correct. Because we have no laws or ordinances that prohibit the sale of introduced or invasive plants (some states do), they are widely available. What we can do at this point is to be informed and avoid buying them.
What are some of the popular, non-native plants sold in local nurseries and garden centers?
In March, 2016 we wrote about Bradford Callery Pear, (Pyrus calleryana); In June, 2016 it was Acer platanoides, Norway Maple; in July, 2016, we wrote about Burning Bush, (Euonymus alatus); and in August, 2016, Winter Creeper, (Euonymus fortunei). Unfortunately, these are all available at local nurseries and garden centers. A few more garden center boarders – invasives and aggressors – are listed below; most, having few natural predators, form un-challenged thickets at the expense of our native plants.
- Butterfly Bush (Buddleia davidii): This vigorous, nectar-producing butterfly attractor is an attractive shrub with fragrant, colored flower spikes, It self-seeds prolifically, however, and before long your planting bed will be overcome with a Buddleia thicket which crowds out everything else. It is classified as noxious weed in Oregon and Washington.
- English Ivy (Hedera helix): This popular and sometimes very lovely vine easily goes astray, spreading throughout woody areas and gardens, choking out other vegetation. English ivy kills trees and shrubs by smothering them.
- Heavenly Bamboo (Nandina domestica): This is not a bamboo, in spite of its popular common name. All parts of the plant are toxic, especially to Cedar Waxwings, cats and grazing animals, resulting in many deaths. Heavenly Bamboo crowds out other plants with prolific seeds and underground stems.
- Japanese Barberry (Berberis thunbergii) : This shrub is banned in Wisconsin and Massachusetts. It displaces native plants with prolific, bird-dispersed seeds, and harbors ticks (due to the high humidity in its dense foliage) mice, and, as a result, lyme disease.
- Japanese Spirea (Spiraea japonica): this plant harbors many insects and diseases but still outcompetes and replaces native plants. Its seeds, dispersed by birds, form dense thickets which are very tolerant to many conditions. It impedes the germination of native seeds.
- Japanese Wisteria (Wisteria floribunda): This very adaptable vine shades out other plants and girdles trees and shrubs as it climbs, cutting off nutrients by choking the trunks and producing dense shade.
- Maiden Grass/Chinese Silver Grass Miscanthus sinensis: More than 50 ornamental varieties of this grass are sold in the United States. The wind-dispersed, viable seed forms thickets which are very adaptable to many conditions, choking out native plants. This is a very popular ornamental grass which is popular to use in a lot of landscaping.
- Periwinkle Vinca minor: ( not V. major).This groundcover forms dense, extensive mats, choking out other plants. It harbors blights and is allelopathic, meaning that its chemical compounds inhibit the growth of nearby plants.
- Privet (Ligustrum sp): This popular hedge plant is toxic to pets and mildly toxic to humans. Thousands of fruits outcompete and replace natives. The seeds, dispersed by birds, form very dense thickets. Compounds in the leaves protect the plant from feeding insects, so it is “trouble free” for the hedge-growing home owner.
For more important information about non-native plants, read Plant Invaders of Mid Atlantic Natural Areas by Swearingen, Reshetiloff, Slattery, and Zwicker
Go to www.MAIPC, the Mid Atlantic Invasive Plant Council for additional plant lists.
Native plant alternatives to exotics can be found in the Brooklyn Botanical Garden’s Native Alternatives to Invasive Plants. In addition, be sure to visit the web sites: