by Terence P Ward
The Department of Environmental Conservation, the state department charged with stewardship over the natural world, has begun enforcing a law that will ban or regulate a number of invasive species that are wreaking havoc on native flora and fauna. While some of the newly designated species are dramatically destructive—Eurasian boars can each destroy 11 acres of wetlands in their lifetime—most are quietly taking over the tract of woods out back, encroaching on the sound-barrier trees along highways, or choking the banks of streams. The measure, which was passed into law last July and went into effect in March, “prohibits or regulates the possession, transport, importation, sale, purchase and introduction” of a total of 153 types of animals, plants, algae, and fungi.
Few people are as aware of the extent of the invasive problem as John Messerschmidt. His High Falls company, Poison Ivy Patrol Specialty Landscaping, has found a niche in identifying and removing invasive plants from Hudson Valley backyards. “People don’t know—they think they have a wild backyard, but they don’t know what they’ve gotten themselves i
Japanese Knotweed, though beautiful, chokes out natural
nto.” That’s because the vibrant green vines draped on the trees and the leggy bushes that produce pretty white flowers are often visitors from out of town, and they are killing the same natural-looking landscape that may have convinced them to buy the house in the first place. “In the spring they call for poison ivy removal, and I point out how unhealthy their woods are. Deer don’t eat these plants, insects and birds don’t like them, and it creates a big dead zone around the yard.”
The original focus of Messerschmidt’s business—removing the unwelcome, but native, poison ivy by hand—led him to recognize the invasive species problem. “I started noticing all these vines,” he said. “Grape vines got onto my radar, then I noticed bittersweet, barberry, multiflora rose, all just about everywhere. You can see them as you drive along the Thruway, climbing up and killing trees,” often because the added weight makes them vulnerable to breaking during winter storms.
Finally having a law to clamp down on the distribution of these and other species should help; many of the worst offenders have been sold as landscaping, often because they are “deer resistant.” The fact that deer and other animals won’t eat plants like the burning bush, which turns a vibrant crimson in the autumn, is part of the reason why they have an advantage over native plants. One of the entries on the new list, Japanese barberry, can continue to be sold for another year, as gardening shops deplete their existing stock. That particular bush, characterized by attractive red berries, has been shown to harbor the ticks that carry Lyme disease under the cool, dark canopies it creates by pushing into areas grazed by deer, who won’t touch the stuff.
Removing invasive plants alongside poison ivy also makes sense because they tend to like the same environments. “They like disturbed soil,” Messerschmidt said, the kind that is left behind from lot clearing and new construction near existing woodland tracts. “They’ll grow where the soil is damaged and unhealthy, and where it’s acidic.” The removal process is also similar, in that it takes a long, sustained effort to make it work—think three to five years in most cases. Messerschmidt recalled a recent discovery on one of his properties, a couple of stands of Japanese knotweed, which has moved from the lower Esopus into the Rondout Creek. They are each “about the size of a kitchen table, which is not that big. I can take them out with two to three guys working for a day, maybe two.” To make sure that this plant, which is called “the scourge of Ulster and Dutchess counties,” does not return requires annual visits to remove regrowth for several years. Cutting it at the wrong time of year “could make it go dormant for up to 20 years” before sprouting again. The deep roots break easily when digging it out, which can lead to the plant actually spreading faster, as each broken end will grow. “In September, it produces a pretty white flower, which floats downstream or downwind to start a new plant.”
That’s typical of invasives: they are adapted to aggressively propagate as a defense against predation, and those mechanisms wreak havoc absent any predators. Removing them is much less costly when the incursion is caught early, and can become impossible if allowed to go too long without intervention.
Diane Greenberg-Groeters, who owns Catskill Native Nursery in Kerhonkson, thinks that it’s best to avoid imported plants, even if they are not listed as invasive. “Almost 80 percent of the nursery trade is Asian and European plants; these are mostly what people garden with. Most are not invasive, but they also offer little to support our local ecosystems.” she said. “Ninety-six percent of native birds rear their young on insects [that] can only breed on specific native plants, [and] they lack the ability to overcome [invasive] plants’ chemical defenses and cannot use them as a food source. With more invasive plants there are fewer native insects and therefore, fewer native birds. This is also true for insect eating amphibians such salamanders, toads, and frogs. When we see our gardens, parks, and wild spaces filled with plants like barberry, burning bush, Norway maple, purple loosestrife, and autumn olive, what we are also seeing are places that cannot support our bird and amphibian populations.”
Planting a newly cleared area with native plants, or even just allowing local flora to move back in, helps restore that balance to the ecosystem out back. The first step toward that end is identification. The DEC has a link to pictures of all regulated and prohibited plants, and Messerschmidt maintains a “ten most (un)wanted” list. In addition, Catskill Native Nursery has a list of alternatives on their website under “resources.”