Ahh spring. I, like so many others, am chomping at the bit to spruce up my yard with new plantings. This winter took its toll on “landscaped” areas. Shrubs and small trees succumbed to ice and heavy wet snow with snapped branches. The melting snow and rain turned bare areas into mud flats. Yes I’m ready.
However, as I skim through nursery catalogues and stroll through garden centers, I am surprised at the amount of invasive plants available for sale. Able to silently creep over vast expanses of land, these aggressive plants wreak havoc on local ecosystems.
The majority of invasive plants are also nonnatives introduced from other continents, states, ecosystems and habitats. Many nonnative plants have great economic value for agriculture, forestry, horticulture and other industries and pose little to no threat to our natural ecosystems. Others have become invasive and pose a serious ecological threat.
Plants are considered invasive if they spread out of control, dominating the local environment and crowding out native plants. Because they have been introduced into an environment in which they did not evolve, there are no natural predators, parasites or other controls to keep these plants in check.
Invasive plants grow fast and mature early in the season and reproduce profusely. Some invasive vines actually bring down trees by their sheer weight.
They outcompete native plants for light, water and nutrients, eliminate entire native plant communities and change the composition of the landscape. The ecological balance of plants, animals, soil and water achieved over thousands of years is destroyed.
As native plants are displaced, animal populations that rely on the plants for food and shelter also decline. When invasive plants take over wetlands, forests or meadows, we lose both the native plants and habitats needed by local wildlife.
In the United States, invasive plants already infest more than 100 million acres and continue to increase by 8–20 percent annually.
Once established, invasive plants require enormous amounts of time, labor and money to control or eliminate them. Invasive species cost the United States an estimated $34.7 billion each year in control efforts and agricultural losses.
Recreational activities such as boating, bird watching, fishing and exploring are also affected. Some invasive plants become so thick that it is impossible to access waterways, forests and other areas.
Estimates indicate that non-native plants infest 4,600 new acres of federal land each day. Each year, non-natives spread into an area larger than the state of Delaware.
Overall, invasive plants threaten every aspect of the North American environment including National Wildlife refuges, national parks, recreation areas, wilderness areas, forests, wetlands and croplands.
So be careful when choosing plants. Some common landscape plants are invasive. Many times homeowners unknowingly introduce an invasive plant because they didn’t know that it could become a menace in the wild.
Become familiar with invasive plant species in your area and avoid them. Ask for native plant alternatives at your nursery. If you already have invasive plants on your property, consider removing them and replacing them with native species. Here are a few troublesome plants to avoid. Instead, try planting one of the suggested native alternative plants.
Purple Loosestrife (Lythrum salicaria)
Dense Blazing Star (Liatris spicata)
Cardinal Flower (Lobelia cardinalis)
Obedient Plant (Physostegia virginiana)
Chinese Wisteria (Wisteria sinensis)
Japanese Wisteria (Wisteria floribunda)
American Wisteria (Wisteria fructescens)
Trumpet Creeper (Campsis radicans)
Trumpet Honeysuckle (Lonicera sempervirens)
Winged Burning Bush (Euonymous alata)
Red Chokeberry (Aronia arbutifolia)
Virginia Sweetspire (Itea virginica)
Highbush Blueberry (Vaccinium orymbosum)
Bradford Pear (Pyrus calleryana ‘Bradford’)
Redbud (Cercis canadensis)
Serviceberry (Amelanchier canadensis)
Southern Arrowwood (Viburnum dentatum)
The National Park Service and U.S. Fish and Wildlife Service have put together a color guide, “Plant Invaders of Mid-Atlantic Natural Areas” which describes common invasive plants and alternative native plants to use in their place. Supplies are extremely limited. For small orders, or if your organization is interested in reprinting this publication, contact the U.S. Fish and Wildlife Service, Chesapeake Bay Field Office at 410-573-4500.
Copies can also be downloaded from www.nps.gov/plants/alien/pubs/midatlantic.
For information, visit the Plant Conservation Alliance’s Alien Plant Working Group web site at www.nps.gov/plants/alien/ or the USFWS, Chesapeake Bay Field
Office’s BayScapes web site at www.fws.gov/r5cbfo/Bayscapes