Picture newly laid black asphalt bulging up here and there, then green plants pushing on through and out to the light, ready to sprout up to six or eight feet high. Who needs invaders from outer space when we have Japanese knotweed to try to eliminate? Whack and dig year after year and it just keeps coming back.
On Aug. 5 about 65 Japanese knotweed fighters met in North Creek to learn how to combat this invasive nuisance, better known as “Mexican bamboo” in the Adirondacks. I needed inspiration as a North Creek “coordinator” and I got it. Knotweed can send its rhizomes (a type of root/stem that can sprout new plants all along it) under two lane concrete roads and emerge ready to go on the other side. In England people who “plant or otherwise cause Japanese knotweed to grow in the wild” can be subject to fin es of $15,000 pounds or six months in jail! It is a terrible problem for home owners because it can destroy a foundation.
Drive in Vermont and on to even Nova Scotia as I did recently and you will see Fallopia japonica (formerly Polygonum cuspidata) lining the streams and rivers in untold numbers of acres. It is impossible for fishermen and other recreationists to get through the jungle to the water. Do we want that in the Adirondacks? We still have a chance to fight it back using the right techniques. Cutting it down once a year is worse than useless so don’t bother doing that. Mowing it by road crews just spreads it down the road because tiny pieces of the plant can sprout and grow. With weekly mowing for many months you probably can beat it, but you need a place accessible enough to mow completely.
However, when each stem is injected with the right herbicide at the right time, in the late summer and fall before frost, the herbicide is sent down into the rhizomes along with the nutrients the plant is storing for the next spring and 95% of the plants will die. Usually a few sprouts will come up the next year or two and have to be sprayed individually at the same time of year, if the stems are less than finger size and too small to inject. Landowners can do this on their own property with the right equipment and herbicide but we have a professional in the area now who can treat knotweed through a supported program run by the Town of Inlet. Donations are needed and expected if your treatment is successful to be able to continue the effort. Google noknotweed.org for more information or you can call me if necessary at 251-3772.