This is part of a series with Perfect Earth Project, a nonprofit dedicated to toxic-free, ecological gardening, on how you can be more sustainable in your landscapes at home.
Step outside for a nature walk and you’re likely to encounter invasive plants—barberry and burning bush, to name just two that are fast encroaching on Northeast woodlands. But you may be surprised to learn that there are nurseries and online plant stores selling these self-same invasive plants. Evelyn Beaury, a scientist and assistant curator at the New York Botanical Garden’s Center for Conservation and Restoration Ecology, has been studying the effects of the nursery trade on invasive plant spread. “About 60 percent of plants we’ve recognized as invasive are still being sold through commercial nursery trade in the U.S.,” she says. And as a result, people are still buying and planting them in their gardens. We talked with Beaury to explain why we should be concerned about this and what we can all do to slow the spread of invasives.
What is an invasive plant anyway? An invasive plant, according to Beaury, is one “introduced to an area by humans—it wouldn’t have gotten there on its own—and has spread rapidly, causing measurable negative socioeconomic or ecological impacts.” About half of the species that are considered invasives today were intentionally brought to the U.S. for ornamental, agricultural, medicinal, and other plant trade purposes.
“Invasive plants can dominate an ecosystem,” says Beaury. Their leaves and seeds can be toxic to wildlife. They can outcompete native plants. And they can completely alter the terrain: clogging up waterways or transforming forest structures from closed to open canopy. Stiltgrass (Microstegium vimineum), for example, is proliferating on the East Coast, notes Beaury. It creates dense mats of vegetation that cover the forest floor, which prevents native tree seedlings from taking root. Cheatgrass (Bromus tectorum) on the West Coast is doing the same thing, turning the forest into grassland. “If those invasive species come in first, it’s really hard for native species to recruit seedlings,” she says. When these plants out-compete native ones, they decrease the diversity of an ecosystem. And all these changes harm the wildlife that rely on plants they co-evolved with for food and shelter.
There are also financial consequences. The control of invasive species in the U.S. costs an estimated $20 billion, not to mention the environmental and health damage that many of the controls themselves (such as the use of pesticides) cause. Invasive species can diminish property values as well—who wants to buy a house with an infestation of knotweed? “The big thing with invasives is that they’re just making all of our other issues with land management more challenging and more expensive,” says Beaury. We need to be proactive since it’s so much harder to deal with an infestation than to stop one before it starts.
Here’s what you can do:
If you see something, say something.
Invasive species bans are not always enforced at nurseries. It’s up to consumers to take action. If you see something (a barberry for sale, for instance), say something. Talk to your nursery about the problems with invasives. Recommend they consult invasive species lists (see below) if they’re uninformed and encourage them to stock more native plants. Ask them not to sell invasives—and keep asking until they stop. Tell your friends. Post on social media. Talk to your elected officials. Consumers have power. Bees, butterflies, birds, and other wildlife need all of us!
Think beyond your local area.
As our climate changes, so does the range of where invasives grow. Certain non-native plants that were traditionally considered invasive in, say, Virginia, are now creeping north as our winters warm. “We’ve been advocating for thinking more regionally rather than by county or state,” says Beaury. Just because a plant isn’t a designated invasive in your state doesn’t mean it isn’t. “A lot of our invasive species problems in New England are similar to the problems folks are dealing with in other regions, such as similar species of concern in parts of Oregon and Washington,” she says. The best way to stop the spread is by not planting them. Beaury suggests playing it safe: Do not buy non-native plants considered invasive anywhere in the U.S., even if they’re technically allowed in your state. Check out USDA invasive lists and avoid buying any non-native plant described as aggressive or is known to spread rapidly.
