Invasive Plant Information for Vermont:
Foreign Invaders from the Local Garden Nursery |
By Anne Margolis (from the Rutland Herald February 29, 2003)
Even though it’s cold outside, you may be warmed by the colorful nursery catalogs that seem to arrive in the mail almost daily. But as your eyes drift over the snow-blanketed landscape, envisioning exotic-looking perennials, try to remember just how exotic some of those plants really can be.
Non-native (also called alien or non-indigenous) plants come from elsewhere, but though they are not natural in our ecosystem, they do not necessarily pose a threat to it either. Most will only, at worst, jump the garden border and take hold here and there.
However, a non-native plant can become an invasive plant when it becomes so successful that it outcompetes and displaces our native plants. Invasives cause real havoc to our native ecosystems but nevertheless are often planted as ornamentals and landscape specimens for that very same reason – their vigor.
Invasives are among the most pressing environmental problems today; scientists believe they have contributed to the decline of 42 percent of the species on the federal endangered and threatened species lists. We as gardeners have the responsibility and ability to choose native alternatives, which have evolved along with the other animals and plants that make up our local ecosystem.
For instance, you might be considering a Norway maple for your yard. It is native to Europe and was originally brought here as a landscape plant; but it is so adaptable that it has spread throughout New England on its own. One reason for its success is that (not unlike some native trees) its roots exude a chemical thought to inhibit the growth of any other species under its canopy.
There are many excellent alternatives to the Norway maple, including native red maple (also adaptable to many sites) and yellow birch. Red maple has colorful leaves in the fall and bright red twigs in the winter, and its pinkish buds add the first touches of color to the greening spring landscape. Yellow birch also puts forth early buds, which, along with its seeds and catkins, are a staple for ruffed grouse, red squirrels, and songbirds.
Maybe you’re seeking a colorful shrub, like the bright-red-autumn-leaved winged burning bush (not to be confused with eastern burning bush, a shrub with yellow autumn leaves native to the Midwest), or one that produces bright berries, like the Japanese barberry. Winged burning bush, native to Asia, grows easily and reproduces rapidly but has the potential to become as invasive here as it already is in the Mid-Atlantic States, where it crowds out understory plants. Japanese barberry, native to Europe and China, spreads quickly by seeds, which, contained in their fleshy red fruits, are attractive to birds. However, its sharp spines also impede wildlife movement, while the bush itself crowds out many native plants.
Instead of these two intruders, try downy serviceberry, which sports lovely clusters of drooping, fragrant, white flower clusters in spring. Better yet, those flowers become fruits that can be made into excellent jellies, jams, and pies – if you can get to them before the songbirds, turkeys, grouse, doves, foxes, raccoons, and squirrels. Native blueberry and sumac can also fulfill the niche for bright autumn foliage while providing a delicious fall crop.
No discussion of invasive species can ignore purple loosestrife. This beautiful aquatic plant is called “the purple plague” for its ability to reproduce and spread rapidly; it can propagate vegetatively or by the millions of tiny seeds it produces. Once cultivated in gardens, it now chokes wetlands across the country.
Unfortunately, some nurseries are leading people to believe that certain cultivars of loosestrife are sterile. According to Bern Blossey, director of the Biological Control of Non-Indigenous Plants Program at Cornell, “the claim that cultivars of purple loosestrife are sterile is totally false.”
Because of the dangers it poses, selling, distributing, and transporting purple loosestrife are illegal activities in Vermont and New Hampshire. The yellow-flowered garden loosestrife is also considered highly invasive. So instead, consider planting native bee balm, blazing star, common joe-pye weed, figworts, or purple coneflower.
Some other invasives on the most-wanted list include: wintercreeper and English ivy, which are groundcovers; oriental bittersweet, a fast-growing vine; Chinese and European privet, common and glossy buckthorn, and Japanese, Amur, Morrow’s, and Tatarian honeysuckle, which are fast-growing shrubs; and Japanese knotweed, coltsfoot, and most common reed (or Phragmites) populations, all found in wet areas.
For more information, visit www.invasive.org/eastern/, which lists invasives in the eastern U.S., http://invasives.eeb.uconn.edu/ipane/, the Invasive Plant Atlas of New England, or www.newfs.org/conserve/, where the New England Wildflower Society has put together a great list of native alternatives. Your regional cooperative extension or state agriculture department are also great resources. When in doubt, just remember – keep it local!
BIO: Anne Margolis is the assistant editor of Northern Woodlands magazine in Corinth, Vermont. Illustration by Adelaide Tyrol. Support for this article series is provided by the Upper Valley Community Foundation’s Wellborn Ecology Fund: wef@nhcf.org.
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