Montshire Minute: Invasive Exotics

Originally aired during the week of June 14, 1999

Monday

Its bright fuschia flower makes it one of the most beautiful plants in our region. But there's a dark side to purple loosestrife. This plant is an exotic invasive. That is, it was accidentally imported from Europe, and has no natural predators on this continent. It spreads quickly, invading marshes and lake shores by choking out cattails and other native wetland plants. Purple loosestrife is just one example of the many "exotic invasive" plants which have become a big challenge for conservationists. You're invited to join us for a discussion about what we can do to prevent the spread of these plants on Thursday, June 17, at 7:30 pm at Montshire. Speakers will be Chris Mattrick, rare plant curator of the New England Wildflower Society, and Carl Pagel, director of the biological control program for purple loosestrife, Vermont Department of Environmental Conservation.

Tuesday

Purple loosestrife has been called public enemy #1 on federal lands by the US Wildlife Fish and Wildlife Service. This plant, identified in the summer by its tall crown of purple-pink flowers, is found in 26 states, and covers about 400,000 acres of wetland. It grows like, well, like a weed. One mature purple loosestrife plant can produce several million seeds in a single summer. Fragments cut off from the root or stem can form new plants. This European native pushes out native vegetation like cattails and sedges, perfect habitat for many familiar birds like the American bittern. No creature in North America seems to seek out the plant for food, so purple loosestrife has spread without interruption. This plant also invades shallow waters, ruining spawning grounds of the northern pike.

Wednesday

Over the past few years, much of our wetland has been invaded by a problem plant called purple loosestrife. Pretty though it may be, this plant is causing serious damage to native wetland inhabitants. It's an easy plant to spot: the bright fuchsia colored flower spikes can often be seen along roadsides all throughout the northeast. Why is purple loosestrife such a problem here and not in Europe? Over 100 insect species feed on purple loosestrife in Europe and Asia. These insects, along with disease, keep purple loosestrife growth under control in its natural habitat. But none of these natural enemies live in North America. The plant has no natural predators, and burning or mowing loosestrife often just encourages its spread. Once native plants are choked out, the wildlife that depends on them for food and shelter are also eliminated.

Thursday

You're invited to join us tonight for a discussion about what we can do to prevent the spread of problem plants like purple loosestrife on Thursday, June 17, at 7:30 pm at Montshire. Speakers will be Chris Mattrick, rare plant curator of the New England Wildflower Society, and Carl Pagel, director of the biological control program for purple loosestrife, Vermont Department of Environmental Conservation. Several methods have been used to fight purple loosestrife. Isolated patches of loosestrife can be wiped out by uprooting the plant by hand, burning it, or treating it with herbicides. However, these methods won't work against large, well established populations and can also disrupt native plants. According to the Vermont Agency of Natural Resources, biological controls are a promising way of controlling this non-native plant.

Friday

Scientists have achieved success in controlling the spread of some non-native plants like purple loosestrife by using bio-controls. How do they work? Basically, bio-controls use a plant's natural enemies against it. Bio-control began in Vermont in 1995 with the release of three types of European insects by the U.S. Fish and Wildlife Service. Three summers ago, the Vermont Department of Environmental Conservation began releasing two more species of leaf-eating beetles. These "purple-plant eaters" have done a good job reducing purple loosestrife. The release of the insects were approved after rigorous testing, to insure they did not feed on crops or native plants. You can help stop the spread of purple loosestrife by hand-pulling isolated plants by the roots and dispose drying and burning. Make sure your local garden center or nursery is not selling purple loosestrife.