japanese knott weed

[knotty10]

last spring, as an experiment I cut off the tops of the emerging Japanese knott weed in the lane behind my house, then filled the hollow stalks with a heavy duty weed killer. The treated stalks never grew any taller and appeared very shriveled and limp. I've been out several times in the past few weeks to see if this years weeds have started emerging. I've been unable to find any yet although the other side of the fence the weeds are about a foot high. Comments Please

[Chris]

Maybe you killed them, though I hear they are near impossible to get rid of. I would definitely wait longer before declaring victory.

[Charles]

Maybe you killed them, though I hear they are near impossible to get rid of. I would definitely wait longer before declaring victory.
They are really hard to get rid of - any little bit of root left over tends to regenerate - burning is not good as the spores can get carried by the heat and wind.

I have heard that the only real way is to bury them in an impervious liner, but even then the spores can live on for many many years.