Backyard Gardening

By Kathy Dorman

A couple of months ago, my sister called me. She was doing a children’s sermon for her church. She wanted to talk about God, Moses, and the burning bush (Exodus 3). She had seeds for the burning bush plant and wanted information about it. I did some research and gave her the bad news. Burning bush (Euonymus alatus) is invasive and is now classified as a Class B noxious weed by the Pennsylvania Department of Agriculture. Over 20 states and many Canadian provinces have now designated Euonymus alatus as invasive, especially in the eastern half of North America.

A noxious weed is defined as a plant that can be “injurious to public health, crops, livestock, agricultural land or other property and cannot be sold, transported, planted, or otherwise propagated in Pennsylvania.” The “Garden Police” will not come to arrest you if you already have an invasive burning bush growing on your property. However, they might lecture you about still having it!

I have seen many of the invasive burning bushes in central Pennsylvania. Since the leaves turn spectacularly brilliant, almost neon red, in fall, they are easy to spot at that time. (See Photo 1). According to North Carolina State University Extension, the burning bush can reach heights of 20 feet but can easily survive severe pruning. Its oval, pointed, finely serrated leaves are one to three inches long and about an inch wide. The leaves grow in pairs opposite each other along the branches. Stems often have elongated corky ridges or wings (See Photo 2). Yellow-green flowers emerge in early spring, and fruits ripen in the fall. The fruit capsule color may be variable, but the seeds are orange-red.

A related species, the American burning bush (Euonymus atropurpureus), is native to Pennsylvania. It is also called eastern wahoo or Indian arrowwood. The fall leaf color can be yellow or red. These native trees can grow about five feet taller than their invasive cousins. Their growth habit is gangly, not compact and rounded. The elliptical, opposite leaves are bigger in the native species (three to six inches long and wide) and are hairy on the undersides. The stems of the American burning bush do not have wings. Flowers are purple and bloom in late spring/early summer. The fruit and seed color is red or purple.

The two main reasons Euonymus alatus is noxiously invasive are its environmental adaptability and reproductive capacity. It can thrive in full sun, partial shade, and even deep shade in the forest understory. Once established, burning bushes can form dense thickets, crowding out native species. If there is good drainage, invasive burning bushes can grow in various soil types, such as clay, silt, or sand. They can grow in acidic, neutral, or alkaline soils.

The invasive burning bush is a very prolific seed producer. Hundreds of seedlings can be found growing under a mature burning bush. Many species of birds will eat the fruit capsules and spread the seeds far and wide. Researchers at the University of Illinois have found that fruits from invasive species may have a lower nutritional value, and our native birds prefer native berries. As the invasive burning bush expands its territory, the native food resources for native wildlife will continue to diminish.

I realize how pretty the burning bushes are when the leaves change to their red fall color. It would be difficult to dig up these plants after spending money, energy, and time to plant them. However, according to Penn State University Extension, “the best way to prevent burning bush invasions into natural areas is to remove the closest seed source.”

There are lots of native shrubs that can be planted instead of the invasive burning bush. They can provide comparable fall color and winter interest. American burning bush seedlings can be purchased from reputable nurseries, especially the ones that only sell native plants. Ensure that the plants are Euonymus atropurpureus and not E. alatus. We do not have any burning bushes growing on our property, and I have no plans to plant any. It will soon be illegal to plant invasive burning bushes in Pennsylvania. I have planted many native alternatives, including blueberry (Vaccinium corymbosum) chokeberry (Aronia spp.), dogwood (Cornus spp., now known as Swida spp.), ninebark (Physocarpus opulifolius), oakleaf hydrangea (Hydrangea quercifolia), spicebush (Lindera benzoin), and witch hazel (Hamamelis virginiana). Other options include serviceberry (Amelanchier spp.), sumac (Rhus spp.), sweetspire (Itea virginica), and viburnum (Viburnum spp.). Please help our native environment by removing invasive burning bushes growing on your property!

Kathryn Dorman has been a certified Penn State Extension Master Gardener of Clinton County since 2017. She can be reached at clintonmg@psu.edu or through the Master Gardener Hotline in Clinton County at (570) 858-0198.