Invasive plants are non-native species that are displacing native plants. Not all non-native plants are invasive. Growing along the edges of roadways and paths; moving into fields, forests and wetlands; appearing in our gardens: Our neighborhoods and wild landscapes are threatened by introduced plants that do not support the complexity of living organisms that co-evolved with plants native to our area. In the absence of natural predators and pathogens, the interlopers naturalize, compete with and displace native flora, spread rapidly, and overpopulate the land. Their seeds are spread by birds, wildlife, livestock, water, and wind. We, humans, carry seeds on our shoes, car and truck tires, mowers, and other machinery.
Motivated by awareness that our survival depends on each of us caring for landscapes that support a viable, native food web with a diverse population of pollinators (paraphrasing ecologist Doug Tallamy), let’s look at a few of the 36 invasive species and 33 likely invasives listed by the Massachusetts Invasive Plant Advisory Group. Very many of these 69 species are undermining our personal and public lands.
Oriental bittersweet (Celastrus orbiculatus), barberry (Berberis thunbergii), and Norway Maple (Acer platanoides) persist as favorites of the landscaping trade despite being listed as prohibited in many states. These plants were first introduced in the 18th or 19th century for their aesthetic appeal, hardiness, drought tolerance, low maintenance requirements, and deer resistance. Stiltgrass (Microstegium vimineum) is reported to have arrived as packing material in shipments from China. It is likely that you as I, dear reader, and/or your neighbors—deliberately or neglectfully—grow one or all of the species on this small list.
Stiltgrass is, literally, all around us. It is among the greatest threats to our forests and wetlands.
The photographs by Dr. S. Luke Flory, Professor and Associate Chair, Invasion Ecology at the University of Florida, tell a convincing story. Two of the images appear in Berkshire writer Margaret Roach’s New York Times feature, “Meet Stiltgrass, Your New Garden Adversary: Here’s how to identify this fast-spreading invasive weed—and what to do about it, if you find it on your property.” Published on June 8, 2022, it is a must read.
Walking along country roads and driving main thoroughfares, stretches of unnatural, tangled vegetation reach from the ground up to about 60 feet. Ropes of bittersweet obscure the presence of great tree trunks and their muscular limbs—prized shrubs, too. Why aren’t the neighbors cutting the vines away from what appear to be wonderful oaks and graceful shadbush smothered under the dense foliage and weight of the invasive vines?
The tall column above is a summer season view of bittersweet’s aggressive habit. Learn more through Penn State Extension.
Once we’ve rooted out invasive plants, there’s the critical work of disposing of them so that they do not propagate. Find excellent directions here.
With each of us taking an interest and performing small actions consistently, the diversity of native plant communities—wildflowers, shrubs, trees, and associated organisms—will gain protection from invasive introduced plants. And, of course, grow natives!
