Invasive plants crowd out natives
Toolbox
By Susan Smallheer Rutland Herald - Published: June 18, 2007
SPRINGFIELD — Invasive plants aren't necessarily ugly or odd-looking. And they may be right on Main Street.
But they are on the growing hit list of biologists who worry that the vigorous newcomers might crowd out native species, including the sugar maple.
New Hampshire has put the stately Norway maple on its hit list of invasive plants, citing its effect on the sugar maple by its vigorous growth. Its roots actually give off a chemical that retards the growth of the sugar maple, according to Jan Lambert, a naturalist from Charlestown, N.H., who spoke Thursday to the Sustainable Valley Group.
While Vermont hasn't put the Norway maple on its list, the list contains some surprises, Lambert said.
In addition to the infamous Japanese knotweed and glossy buckthorn, which have earned the ire of landowners and naturalists all over the Northeast, Vermont also bans the sale and purchase of bush honeysuckles.
Vermont's list of common invasive plants in the Connecticut River Valley, Lambert said, is half the length of New Hampshire's.
"We like plants that are easy to take care of," Lambert said. But that vigor gets out of control, taking over native habitats. "We have to be really savvy consumers. The goal is controlling, not eradicating."
New Hampshire in January added burning bush (euonymus alatus), yellow iris (iris pseudocorus) and Norway maple (acer platanoides).
Lambert said Vermont and New Hampshire are trying to crack down on mail order and Internet sales of the banned plants, since local nurseries are following the ban. Mail-order nurseries and sales over the Internet don't follow individual state's bans.
"If you make a wreath of bittersweet, you are actually breaking the law," Lambert said, who said her personal "public enemy" plant was the water chestnut.
Lambert said the water chestnut showed up a few years ago in the U.S. Army Corps of Engineers North Springfield Lake, but after extensive work has been eradicated. Water chestnut is not a big problem in the eastern part of the state, but it is on Lake Champlain and the Hudson River, she said.
And she said the state's best success story is the purple loosestrife, which is being controlled by natural means: A small brown beetle and its yellow larva are eating the plant before it has a chance to bloom and set seed.
Purple loosestrife, which was once a popular garden plant, can crowd out the natural wetlands habitat, and cattails, sedges and rushes are its unintentional victims, she said.
Lambert told the group that the yellow iris, or yellow flag as it is known, is a big problem in Massachusetts, where it is taking over wetlands, eliminating native species. It is banned from being sold in New Hampshire, but it is readily available through the Internet.
Many unethical companies simply label the problem plants as "dwarf" varieties, she said. Don't ever buy from a mail-order company that doesn't give a plant's formal Latin name, she said.
Lambert said that government is sometimes responsible: The multiflora rose was planted decades ago, with the support of the government, as a living hedge, with its rosehips a good food for wildlife.
It has brought mockingbirds and cedar waxwings into the area, she said.
But it can take over a field, and is the bane of farmers, she said.
Likewise, buckthorn was also sold as a hedge, but now it is the bane of landowners, who say it crowds out native plants.
Willis Wood, a Weathersfield farmer who was at the meeting, said the Norway maple is quite common. The stately row of maples in front of the old Jones & Lamson Machine Tool Co. in downtown Springfield are Norway maples.
The Norway maple, which is tolerant of road salt and soil compaction, more so than the sugar maple, was also planted in the Memorial Grove at the Weathersfield Center Meeting House, as replacement trees. Wood, the town's tree warden, said he was against it, but was overruled.
You can tell a Norway maple from a sugar maple by the telltale white sap that comes out of a leaf stem when it's pulled from a tree, Lambert said.
Wood said he had several acres of Japanese knotweed, and a recent, worrisome and fast-moving infestation of garlic mustard, and plenty of glossy buckthorn.
So far, he said, he didn't have any answers for getting rid of the fast-spreading plants.
The two states share a ban on oriental bittersweet, common buckthorn, glossy buckthorn, garlic mustard, Japanese knotweed, Eurasian milfoil, purple loosestrife and shrub honeysuckles.
New Hampshire has added autumn olive, European barberry, Japanese barberry, blunt-leaved privet and multiflora rose to its list of banned plants.
Lambert has worked as a consultant for the towns of Brattleboro, Hartford and Windsor, and the U.S. Fish and Wildlife's Silvio Conte Refuge in removing milfoil from ponds or rivers. She gives talks around the region, trying to raise awareness of the invasive plants that go beyond the purple loosestrife and the Eurasian milfoil, the feathery green plant that is clogging many of Vermont's rivers and ponds.
Lambert had no trouble finding milfoil, which escaped from an aquarium many years ago, at Hoyt's Landing.
Lambert, on a tour of Hoyt's Landing in Springfield before her talk to the group Thursday evening, quickly picked out several invasive plants at Hoyt's, which nonetheless was doing well in warding off some of the species.
There wasn't any Japanese knotweed at the landing itself, but a small island at the mouth of the Black River was being overtaken by the plant, which was introduced in the United States more than 100 years ago as an ornamental plant.
But Lambert said she could quickly pick a beautiful bouquet with the invasive plants at the landing: yellow flag, multiflora rose and dame's rocket, an escaped garden plant, which is on the list of "watch" species, meaning it could become a problem.
But not all invasive plants are all bad.
The black locust tree, a native of Virginia, is now quite common in southern Vermont. The tree is in blossom now, revealing heavy, sweet-smelling white pea-shaped flowers.
But Wood said the wood from the black locust was great for fencing posts, since the wood is so dense it resists rot. And it's great firewood too, he said.
Contact Susan Smallheer at susan.smallheer@rutlandherald.com.
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