Japanese knotweed a resilient invader

Posted Sept. 12, 2008, at 9:05 p.m.
Last modified Jan. 29, 2011, at 12:47 p.m.

Do you know about Japanese knotweed? It is an invasive species that grows on disturbed soils. Many Mainers call it bamboo.

It was imported into this country and is recognized as one of the world’s most invasive species. You probably know that if you have it on your property and you have ever tried pulling it up. You can cut it, dig it up, burn it, dose it with herbicide and it will still be there. As a matter of fact, it seems to thrive on the attention. Actually, when people dig it up, the apparently dead root pieces will regenerate elsehere.

Knotweed is edible and apparently has some medicinal benefits. Apparently Japanese knotweed is a great source for resveratrol. Resveratrol has shown itself to be an anti-cancer agent in nonhuman tests. It is also an anti-inflammatory that apparently has blood-sugar lowering tendencies. Resveratrol is the active ingredient in grape products — read that as wine — that has the possible benefit of keeping French people healthy while they eat their rich foods.

Studies have also shown that resveratrol prolongs the life span of the worm Caenorhabditis elegans and the Drosophila melanogaster, the fruit fly. I guess that is good news for fruit flies and worms at least.

Japanese knotweed is being used as a source for resveratrol by supplement manufacturers.

Maybe we should be cutting the stuff down and drying it and selling it. It certainly is renewable and apparently requires no assistance from us to grow.

Oh yes, there is another medicinal attribute to Japanese knotweed: It is a source of emodin, a nutritional supplement used to regulate bowel motility. It is used in the East as a natural laxative.

Some of us still might not want it around. It does choke out more desirable indigenous plants. As I mentioned earlier, it does not go quietly into the night. There is an international effort to figure out how to control knotweed as it is all over the world, trying to take over road cuts and riverbanks.

Some techniques show promise. A British Web site I came across suggests using Roundup herbicide or 2,4D, which was one of the components of Agent Orange. Yikes! The results are mixed on herbicide use. This is strong stuff.

A more primeval concept is to cut it flat to the ground and cover it with black plastic for a couple of years. I have noticed some of these plots around the countryside. Funny thing is, the remaining taproots will send out new shoots at the edges of the plastic.

There is one more method I just found while writing this, which is a slightly safer, perhaps quickeracting solution. Spray the plants with seawater. Apparently they do not like salt water. Then again, unless you grow seaweed, most terrestrial plants do not like salt water. And what if you are not near the sea?

Well, I suppose there is something to be said for developing the market for Maine Natural Resveratrol. And maybe even Maine All-Natural Emodin.

Please insert your own joke here.

Q: We have a home only 5 years old and well insulated except for the basement. There are also two walkout doors that leak a lot of cold air during the winter. The house is 70 feet long, which makes for a large basement. We are thinking of using Styrofoam insulation applied over 1-by-2-inch strips, which would also leave air space between strips. We have been told this would provide additional insulation.

Does this sound like the proper way to insulate, and do you have any suggestions about those two large doors which we do use? Any ideas you might have would be appreciated. — Donna Taylor, Surry

A: This is an appropriate way to go. You need to seal the air space behind the foam off from the basement. It is better than trying to glue it up.

Cover over the doors with full sheets of foam. All joints should be caulked or foamed around the doors.

Questions for Tom Gocze should be mailed to The Home Page, Bangor Daily News, P.O. Box 1329, Bangor 04402-1329. A library of reference material and a home-project blog are at bangordailynews.com/thehomepage.

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