Green Living – The Alien Invaders
Green Living is series of articles written by Cile Downs, Co-Founding Member of APC and passionate defender of our natural environment. The informative stories, which originally appeared in the East Hampton Star, offer a wide variety of ecologically friendly ways to lighten your footprint on the planet and on our beautiful Creek.
They could be either plants or animals, but we’re talking about plants in this article. Their objective is the complete takeover, to go from New Kid on the
Block to Only Kid on the Block. Sometimes they pretty well succeed. They are called “invasive” species and homeowners are allowed to remove them even in areas of their property that must not be cleared.
“To be called ‘invasive’ a plant has to move aggressively into a new habitat, where it monopolizes resources like light, nutrients, water and space to the detriment of other species,” says Lisa D’Andrea of the East Hampton Natural Resources Department. The native members of your local plant community — woodland, grassland, duneland or whatever — are competitive but have reached a balance over hundreds or thousands of years. Not so these exotic or alien newcomers. “They are survivors and fierce competitors. Most are prolific seed producers and often their seeds remain viable for years. Some may produce several generations in a year; some may reproduce asexually, spreading by roots and stolons. Some even release chemicals that prevent growth of other plants” says Lisa.
One thing greatly to their advantage is that they have left behind all the pests, diseases, and climatic conditions of their original home that might have kept them under control. You might say, why not bring one of those pests here and see if it will control the invader in this habitat? But that ignores the possibility the strange pest also will become invasive and attack native plants. So, it’s not a good idea. It may be a matter of time before something native discovers the alien as a food source, but meanwhile enormous, and one fears irreversible, damage can be done.
Another thing that promotes invasives is the continual transportation around the world of people and goods. We know well by now how diseases, insects or seeds can reach new territories and start their rampage. But at first, who knows they’re dangerous? I, personally, have tenderly nurtured a brand new (to me) invasive plant because it was pretty!
Around here, some of the worst threats are: phragmites, oriental bittersweet, porcelain berry, spotted knapweed, Japanese knotweed, autumn olive and garlic mustard. In no case is a herbicide a good solution. Herbicides are dangerous to use and hard to limit to the target, not to speak of the possible damage to ponds or creeks where rain runoff might carry them.
However, in your own property you can practice intensive warfare against a single plant species, so long as it doesn’t cover a great deal of territory. That’s why you need to:
- Know them by sight
- Check up on what’s growing frequently
- Start destroying them the minute you spot them
No plant known can resist being cut to the ground repeatedly, and that applies even to bittersweet. Cut it down, then cut any sprouts that come up. If it has seeded, pull up the seedlings. If it spreads into grass, mow it. What works for bittersweet ought to work for porcelain berry.
Huge efforts have been devoted to the destruction of Japanese knotweed at Louse Point in Springs, where it once formed a thick hedge in summer that prevented anyone from viewing the bay. We think of this as a pilot project; the question is whether this species can be eliminated. So far, so good. It is a persistent plant which must be cut down and the root dug up. This has to be done repeatedly because any root fragment will generate another plant. If you want to know what it looks like, go down to the pizza shop on Fireplace Road at Fort Pond and look across the street, against the fence. Abolish it early before you have a lot of it.
Autumn olive, on the other hand, if it is cut to the ground and the sprouts from the root trimmed back, will die fairly easily. Eliminate it before birds eat the fruits (rather delicious, actually) and spread it far and wide. Seedlings are easy to pull up.
Garlic mustard can be pulled up easily, but it spreads in wooded, shady places that are usually impossible to mow. This is why their invasion of woodlands is greatly feared — since they prevent growth of new young trees. The main thing to watch for is the seed stalks — get rid of it before it seeds or all is lost.
A DVD that shows you how these aggressive plants look, called “Invaders In Paradise” is available at Amagansett, East Hampton or Bridgehampton libraries. It is part of the series “Long Live Accabonac!”