Invasive Species of Concern in Maryland

photo: James H. Miller, USDA Forest Service, Bugwood.org

ANNAPOLIS, MD (November 18, 2008) - Winged burning bush, winged euonymus, or winged wahoo (Euonymus alatus) is native to Northeastern Asia, Japan and Central China. It was introduced for use as an ornamental plant for landscaping around 1860 and has been widely planted by landscape professionals, homeowners, transportation officials and others for its hardiness, interesting winged stems and deep scarlet red fall foliage. While lovely in these ways, it has escaped from planted sites and poses a serious threat to our native wildlife and natural habitats including forests, coastal scrublands and prairies. Winged euonymus is a threat to mature forests and successional fields because it outcompetes native species. Where it establishes it displaces native plant species and alters habitat for wildlife species. Hundreds of seedlings are often found below the parent plant in what is termed a “seed shadow.” This time of year, the brilliant color of both garden and escaped plants is especially obvious, and so burning bush has been chosen as Maryland Invasive Species Council’s Invader of the Month for November.

Winged euonymus is a multi-stemmed shrub with conspicuously winged, angular branched stems, normally growing 5 to10 feet high. Some mature plants can reach 20 feet in height. The leaves are deciduous, dark green, in pairs along stem, turning brilliant red-purple in autumn. Greenish inconspicuous flowers appear in late spring and mature into red-purple fruits in summer. The fruits have a nutritious, fleshy, red covering called an aril that is attractive to birds, which eat them and spread seeds to new locations. Seeds dispersed this way germinate easily and spread the infestation rapidly. Seed production is prodigious and many seeds germinate where they fall close to the mother plant creating dense beds of seedlings. Winged euonymus also expands locally through vegetative reproduction. Wide usage of this popular landscape ornamental increases the probability that more will continue to escape from cultivation.

Winged euonymus may be confused with the native Euonymus americanus known as strawberry bush or hearts-a-bustin’ which lacks winged stems and is a smaller and sparser branched shrub. Saplings of native sweetgum (Liquidambar styraciflua) with winged stems may also be mistaken for winged burning bush.

In the United States, winged euonymus is present from New England to Georgia and west to Missouri. In Massachusetts it is a prohibited plant, and Connecticut lists it as invasive. It is adaptable to various environmental conditions although it generally does not do as well in very dry areas. It tolerates full shade, grows well in a variety of soil types and pH levels, and has no serious pest problems in North America. It has invaded moist forested sites creating dense thickets that can shade out native herbs and shrubs.

Prevention is the best method for controlling the invasive tendencies of this plant. Native substitutes that provide red fall color and distinctive fruit include red chokeberry (Aronia arbutifolia), fragrant or shining sumac (Rhus aromatica or copallina), highbush blueberry (Vaccinium corymbosum), mapleleaf viburnum (Viburnum acerifolium), silky dogwood (Cornus amomum) or Virginia sweetspire (Itea virginica). Manual, mechanical and chemical means are available to control established euonymus plantings. Seedlings can be pulled by hand. Shrubs can be repeatedly cut to the ground to control resprouts, or cut and treated with systemic herbicides like glyphosate and triclopyr. Seedlings up to twp feet tall can be easily hand-pulled, especially when the soil is moist, due to the fibrous root system. Larger plants can be dug out with a spading fork or pulled with a weed wrench. Larger shrubs can be cut down, but the stump must be ground out or the regrowth clipped. The cut stump can also be painted with glyphosate immediately after cutting, following the label directions. Where populations are so large that cutting or pulling are impractical, glyphosate may be applied as a foliar spray. This treatment is most effective during the early summer months. No biological control options are available at this time.

For more information about and other Invasive Species of Concern, visit www.mdinvasivesp.org

USDA Forest Service Fact Sheet
Ohio State University Fact Sheet

photos available electronically on request.

euonymous bush stems

Winged euonymus, or burning bush, is recognizable in the late fall by its color
James H. Miller, USDA Forest Service, Bugwood.org

NOT WINGED EUONYMOUS
Native strawberry bush has green, unwinged stems
Steven J. Baskauf, http.bioimages.vanderbilt.edu