Program Targets Invasive Plants

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(Host) In Vermont, a new ban on selling or propagating invasive and exotic plants is part of a larger effort to keep them from overpowering native species.

VPR’s Susan Keese reports.

(Keese) Botanist Rose Paul only has to walk a block from her Montpelier office to find examples of invasive exotics. Paul is director of stewardship for the Vermont chapter of the Nature Conservancy.

On a bank between a parking lot and a shady residential street, she identifies several plants that are now illegal to sell or distribute. She points out clumps of bush honeysuckle, whose seeds are spread from yards to woodlands by songbirds. She stops at a tall patch of Japanese knotweed, a once-fashionable dooryard planting. Now she says, it’s crowding out native plants on many Vermont riverbanks:

(Paul) “Japanese knotweed is really a terrific grower and by the first of June, this plant is over six feet tall. So it’s great at shading out anything else that’s underneath it.”

(Keese) Paul says plants like these are part of a worldwide problem that s just beginning to attract serious attention in Vermont. Scott Pfister is a plant pathologist with the Vermont Department of Agriculture.

(Pfister) “The whole concept of invasive species, whether you’re talking zebra mussels in Lake Champlain or Asian longhorn beetles taking out maple trees or Japanese knotweed taking over riparian zones, is really a big issue. It’s probably one of the biggest environmental issues we’ll face in the next century.”

(Keese) A few years ago, at the Legislature’s request, Pfister started working with a committee on a list of invasives to be quarantined. The panel included scientists, state agencies and environmental groups like the Nature Conservancy. It also included members of Vermont’s nursery and landscape trade, a $150 million industry.

Several of the listed species are aquatic pests already monitored by the state. Only a few of the banned plants were still being sold in nurseries when the new rule took effect. Rose Paul of the Nature Conservancy, which protects sensitive natural communities, is worried about some invasive plants she says are still being sold:

(Paul) “I think there are some species that aren’t on the list now that we ought to consider putting on the list in a year or two. Some examples of that would be Norway maples, Japanese barberry or yellow flag iris. All of these things are getting into the natural areas in Vermont now.”

(Keese) Pfister, whose department regulates Vermont’s agricultural trade, says those plants haven’t been studied enough to warrant interfering with interstate commerce. He adds that prohibiting the sale of invasives is just one aspect of a broad campaign:

(Pfister) “The quarantine is one step. Obviously public education, making people aware that certain plants shouldn’t be planted, is an issue. Maybe homeowners will want to go out and try to get rid of some of these plants on their own property.”

(Keese) On his hundred-acre woodlot in Plainfield, Allen Clark is doing just that. Clark, a retired food scientist, is working hard to control the honeysuckle spreading through his woodlands. Using methods he learned volunteering with the Nature Conservancy, he pulls up roots where he can. He cuts and saws the larger shrubs and sprays a bit of herbicide on the stumps, hoping they won t grow back.

(Clark) “Now I’ve got that and I’ll spray just a few drops on the stem… and we’ll just cross our fingers and hope that’s enough to keep that one under control.”

(Keese) Near the uprooted honeysuckle, Clark spies a native dogwood, one of the plants he hopes will now have a better chance at survival.

For Vermont Public Radio, I’m Susan Keese in Plainfield.

Related Links:
New England Wildflower Society
UC Davis Weed Program
Vermont Department of Agriculture

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