Japanese Knotweed a invasive weed (how to kill it)?

Question

I live in Connecticut and this Japanese Knotweed is driving me nuts. I've tried pulling it out by the roots and using Roundup and they keep coming back. I've also put down weed blocker fabric and still continue to grow under and create mountains or just grow through it. Can someone please give some insight on how to kill this weed.

Answer 1

From what i remember reading, knotweed is a member of the bamboo family, which makes it a grass rather than your standard weed, maybe some grass killer rather than weedkiller would have a better effect.

Answer 2

http://www.nps.gov/plants/alien/fact/poc...

It's a dicot, member of the buckwheat family (Polygonaceae), so the standard dicot herbicides work on it pretty well.  IMHO, the best chemical control is to cut the stems by hand and then stump paint immediately with glyphosate.  Repeat as soon as you notice new plants -- and there will be a few.

If you're going with mechanical controls, you really need to dig out the roots, and continue to weed the area assiduously for several years.  Because this produces a lot of soil disturbance (and weed seeds love to come up in disturbed soil), I believe that stump-painting with glyphosate is probably the "greener" option.

Try to get a good groundcover of something non-invasive going ASAP -- preferably something that's pretty cheap in case you have to go back in and do some more removal of the Fallopia.  I've used a couple of sowings of oats in dry sites for this... then when I was sure the Fallopia was gone, put in permanent plantings.