Monday, May 9, 2011

Japanese Knotweed is Quite Dead

Success! The Japanese Knotweed I injected with Round-Up last year appears to be quite dead this spring. Here's the post from last fall so you can see the "before" pictures and the J.K. Injector Tool that was used.

The Knotweed Patch was about 50 x 50 feet and 12 feet high. Now there's just a big dead spot.

Of course, it is not enough to kill an invasive species, if that is just replaced by another invasive species. Here we have Mugwort poised to take over, unless the Autumn Olive can do it first.
Although the larger-stemmed Japanese Knotweed plants have been killed, the smaller stemmed plants on the periphery could not be injected because the large injector needle splits the stem and the Round-Up just drains out. Follow-up is critical for these smaller plants, or they will take over in no time.

1 comment:

Anonymous said...

I am keeping my fingers crossed for you... Our new place near Bennington, VT is being taken over by Japanese Knotweed. We've got 4 patches, one of which is easily 50'x50. We're currently planning to dig the whole thing up at the end of the winter, cover with road tarp, and then new top soil. Needless to say, this stuff is so nasty, I'm worried it won't work.

If you have a second, I have a few questions:
Do you think you'll need to inject these patches again, or are the rhizomes dead as well?
Do you need to dig up the rhizomes?
Are the surrounding plants doing okay? Did the injection leech into the soil?


Susanna in VT