By Bill Sublette
Piedmont Master Gardener
There was a time, before I knew better, when I wanted to add Burning Bush and its stunning fall color to our landscape. As it turns out, I didn’t have to. It crept in on its own from a neighboring property and made itself at home in our patch of woods. Left to its own devices, it will spread throughout the understory.
Burning Bush (Euonymus alatus), a native of east Asia, is just one example of an exotic invasive that is still popular among home gardeners and readily available on the market. Such plants can escape not only into a neighbor’s yard, but also into sensitive natural areas, where they crowd out native plant species that provide food, nesting areas, and other essential support for pollinators, birds and other wildlife.
Many of the invasive plant species infesting U.S. natural areas did not arrive here by accident but were introduced long ago for the nursery trade, and many are still available in stores and online. It’s easy to understand why gardeners are drawn to plants that take off with little care. Unfortunately, some will take off where they shouldn’t go. When we are tempted to buy them, we should look for alternatives, particularly native alternatives that provide an array of ecological benefits.
For instance, if you’re looking for a shrub that provides a rich fall display like that of Burning Bush, consider Virginia Sweetspire (Itea virginica), often available in local garden centers. It offers multiple seasons of interest, from late spring, when its fragrant four-inch spires emerge, to fall, when foliage on its arching stems turns deep red, purple, orange, and yellow. It’s a magnet for birds and pollinators.
Another native option is Highbush Blueberry (Vaccinium corymbosum), a host plant for nearly 300 species of caterpillars. This shallow-rooted cousin of the azalea requires acid soil (pH of 4.5 to 5.2) and a regimen of pruning and other management to optimize berry production (see the April 2019 issue of the Piedmont Master Gardeners’ online newsletter, The Garden Shed, for a helpful guide). But if your desire is simply to have a handsome shrub that provides flowers in spring, color in fall, and food for wildlife and perhaps for you in between, this plant will thrive in your yard with a modicum of care.
For nearly every invasive plant species still commercially available, there are native substitutes that will bring similar visual appeal to your garden. Here are just a few examples:
Japanese Barberry (Berberis thunbergii)
Like Burning Bush, this shrub shows up in our woods uninvited. It was probably brought to us by birds that dined on its berries, which are available into the winter when other food is scarce. Japanese Barberry can also spread through “layering,” when a branch touches the ground and takes root, and will form a dense, spiny thicket in woodlands. Although its spines are relatively soft, they are needle sharp; grabbing one with an ungloved hand can be dangerous. Deer are not inclined to browse this plant, but research has shown that infestations of Japanese Barberry harbor deer ticks that carry Lyme disease—another reason to keep this plant out of our landscapes.
Alternatives: For a widely available option, look to Eastern Ninebark (Physocarpus opulifolius), a largely care-free native that can tolerate clay soils, wet or dry conditions, and sun or partial shade. This resilient plant supports 50 species of caterpillars. Also consider New Jersey Tea (Ceanothus americanus). Like Barberry, this is a low, small-leafed shrub (up to three feet tall) that tolerates dry shade. But unlike the spiney invasive, it is a host plant for the caterpillars of several butterfly species, including Azures. Moreover, this all-American flowering plant can serve up a tasty brew. Its dried leaves were used as a substitute for imported tea during the Revolutionary War.
Yellow-Flag Iris (Iris pseudacorus)
Back when I was new to gardening, a friend gave me a clump of Yellow-Flag Iris—also known as Water Flag. Fortunately, I ignored its common name and planted it in a dry, sunny area. Otherwise, it could have been the gift that kept on giving and giving and giving. This native of Eurasia and Africa is unquestionably an eye-pleaser, with arching grass-like foliage and bright yellow spring blossoms, but if allowed to escape into a wetland or riparian area on this continent, it can wreak havoc. It can spread by rhizomes to form a thick monoculture that drives out native water-loving plants, destroys wildlife habitat and clogs waterways.
Alternatives: Though not quite as showy, the Virginia Blue-flag Iris (Iris virginica) and its close relative the Northern Blue Flag Iris (Iris versicolor) are charming alternatives. In the wild, they are found along the banks of lakes, streams and swamps, where they help clean the water and stabilize soils. In the wetter portions of the home landscape, the Blue Flag Iris is a reliable performer, and it’s ideal for water gardens. I’ve planted them along a roadside drainage area, where they withstand torrents of runoff and snowmelt laced with chemicals.
Chinese Silver Grass (Miscanthus sinensis)
This popular clump-forming grass has been planted in American landscapes for decades. Dozens of ornamental forms are available on the U.S. market. It takes root in disturbed areas and pushes out native vegetation wherever it invades, but even more alarming, it has become a wildfire hazard in our region. Fire officials in the Virginia Department of Forestry point to runaway Miscanthus as the chief culprit in multiple wildfires in Southwest Virginia and are using controlled burns to remove it. One mountain county in North Carolina has dubbed it “wildfire grass.”
Alternatives: There are many attractive native grasses you can plant instead, among them Purple Love Grass (Eragrostis spectabilis), a slow spreader that tolerates hot and dry conditions. Switchgrass (Panicum virgatum) also endures tough conditions and is admired for its year-round appearance and for stabilizing soils. It’s the larval hosts for Skippers and Satyrs (the insect kind). Little Bluestem (Schizachyrium scoparium) also hosts Skipper species and can succeed in clay soils and drought, once established. Birds love its seeds. Bottlebrush Grass (Elymus hystrix), often seen along trails and fire roads on the Blue Ridge, can grow in shade and is larval host of the Northern Pearly Eye butterfly. Plant it where the sun will backlight its bristly seedheads.
For help identifying invasive plants on the market and beneficial alternatives, take a look at a website produced by the Master Gardeners of Northern Virginia at mgnv.org/plants/invasive-plants/. In our area, thanks to the Plant Northern Piedmont Natives campaign, it is now easier to find and purchase native alternatives to invasive plants. Visit piedmontmastergardeners.org/gardening-questions/native-plants/ for a list of participating nurseries and garden centers.