We know that kimmsr - believe me I didn't like using it. In fact I didn't. I got a professional team in who specialise in Knotweed eradication and do the job in full protective gear. JK is that serious a problem here. It's the only time in decades of growing stuff that I have ever resorted to Glyphosate. But the JK was destroying the biodiversity of my ancient broadleaf woodland bit by bit. Biological controls are being researched as a matter of urgency because we know chemicals are not the long term answer. But at present it's all we have. http://www.cabi.org/japaneseknotweedalliance/why-is-it-a-problem/

If you can't beat it, eat it.

JW has large, unlobed, heart-shaped leaves and hollow cane-like stems And does produce an aggressively creeping rootstock instead of a tight clump of growth. As an aside the common nuisance kind in some areas - including much of the Pacific Northwest and Great Britain - is Bohemian knot-weed rather than Japanese. It is an intermediate hybrid resulting from the crossing of Japanese and giant knot-weeds, with the hybrid plants often being male. So that there is not a problem with these male plants reseeding. Just covering large spaces with their vegetative growth if they are not destroyed. I have seen uncontrolled patches in my area occupying square footage the size of entire building lots - and bigger. If still nobody has done anything about it there is an infested bottom-land in the bend of a river in a National Forest east of here that may be something on the order of an acre in extent.

floral_uk z.8/9 SW UK 2 days ago Have you fixed the price? Over here JK could be grounds for a reduction. Could be? Could be? Based on my reading, that is the understatement of the year. https://slate.com/technology/2019/05/japanese-knotweed-invasive-plants.html