Your method is labor-intensive if you're dealing with anything beyond a rootball or two. In my experience (dealing with almost an acre's worth), I found that cutting it down everyday with a scythe as it grew helps take this plant out at the knees come late fall, before the frost, when you smear its leaves (you have to let it grow a foot or two by then, but it grows very fast) with a glyphosate. Those recommending not to use an herbicide are doing people a disfavor. There is a way to treat the growth of this plant without making it a biohazard to native species, and it can be done effectively. I damn near wiped out the entirety of my backyard explosion that stood nine feet tall and spread to almost an acre by the time I purchased the property. The simple fact of the matter is that the repeated cuts of the plant deprive the photosynthesis process. By the time you finally let it grow, the plant is reversing the flow of essential sugars and nutrients back to the rhizomes for winter. Only this time, you are taking with those nutrients a healthy dosage of herbicide. This can only work in the weeks preceding the first frost. I'm not sure what the process is with knotweed growth in regions with no frost.

I have some diy tricks and I've researched this heavily and about to start fighting it but with the help of locals. I am moving into a new home and the backyard is full of this beautiful nightmare plant. I do roofing and I can easily cut this plant down and in the fall dig it down 10" or so and chop the ground up and get rid of the top of the plant like many other videos and I have a trick which is I can lay epdm which is a 90mm thick roofing rubber down and drop a few rocks on it for the spring sprout so it bakes the plant underneath but I don't have $10,000 to spend on the epdm for the area which is approximately 40' wide by 60' long so I did a lot of research. I found pond liner is $4000 to cover that area but that is also not just expensive it's 20mm instead of 90mm. So what I have found and I will be using this as a complete ground covering which is vevor commercial grade ground underlay (often used for paving over ect. 13' x 108' is $300 and befor you say well it's just cheap stuff which it isn't for $1000 I can buy double what I need and legitimately cover not just my entire backyard but do my landscaping with this incorporated under everything including my tiered garden. Any of this knotweed simply can never penetrate through it for the 6-7-9 years people claim it takes to get rid of.

To tackle a huge patch, (make a few trails first on the inside and also blaze a trail around the perimeter), start inside the clump and spray all the stems first, then start at the back and work your way out spraying the undersides of the leaves. Next, go around the perimeter of the patch, carefully spraying all the leaves around the outer edge. Lastly, open your nozzle to full stream and spray over the top of the patch from all sides. Take heart, next year the knotweed will be stunted and easier to spray. 1)The ultimate date for spraying Knotweed is on or around September 15, after the bees are done pollinating. 2) Use 2 ounces Glyphosate and one ounce of a sticker per gallon. 3) Tighten your nozzle to just more than a mist (depending on distance away from the plant) and cover every inch of each plant, first the stem, then leaves and undersides of leaves too if at all possible. 4) The silver bullet to eradicating knotweed is this... when you are done thoroughly spraying... wait for the herbicide to be totally absorbed/dry and spray it all over again one more time! (2nd spray could be done the next day.) After only having 10 percent eradication of the knotweed clumps I treated year after year (for 10 years)... I finally used the double spray in one day technique and found 90% eradication the following season.

It’s on my neighbors property on his side of fence my side is my garden 5 ft. From the fence…. I have a people problem AND a major problem with an invasive plant ! I have tilled mowed and covered just to keep it at bay, ineffectively unfortunately. Sad day. Going 👉 to look for how to solve my people problem 🙏🌱thanks this was helpful you seem like a hard working lady ! 😀

ive been cutting this back like this 3x a year for the past decade and it continues to come up.

Would love to see a three year update

we put black plastic down for a year and it helped a lot

I had a fair size patch of this stuff growing right to the edge of the paved highway. Four years ago I initially cut it down and then after that every time it come back to say under 12 inches I cut it back to ground level every week or ten days. So thereafter starting in spring never let it get any higher than ten inches and then bushwacked it. So guess what after four years I have pretty well beaten it. Still just a few shoots coming up which I quickly cut. But I'm still not letting my guard down.

In the UK this would be illegal. It’s a nightmare this weed.

Wouldn't it be better not to let it get so big in the spring before cutting it. I hope you do another video showing the progress of this technique.

contractor bags are much bigger and thicker and if you want to do a huge stand then you can go even bigger with a silage bag that you can get from a feed store. I like to let it start to grow then if it is in a sunny location put a thick plastic sheet over it to let the sun kill it. Let it start to regrow again and repeat. After a few regrowth and kill cycles you can put a thick mulch down of black walnut or butternut if you can find it and then cover with a very thick weed barrier and mulch on top with a thick mulch. If you want to build beds on top don't puncture the barrier in any way. If you are doing organic gardening and can't use spray then this is the only way I have found.

Hi there! I recently had a landscaper come in for a major yard clean up, which included pulling out a whole bunch of roots (including knotweed), leveling, and planting grass seed. After a couple of weeks, as you can imagine, new sprouts are coming out. I don't think the landscaper understood what they were, and I didn't until I started doing research after the fact. In any case, new grass is definately growing, and I'd very much like to try the: cut it low, let it grow up to 6-10 inches, cut it low again, etc. My concern is mowing, though. I don't want to spread the "infestation" to other areas of the yard. If I cut them very low to the ground then mow, do you think I'll be ok with that?

I am trying two things one I got an old carpet very thick put it over the area that I just cut then 6inches of mulch. second getting a hypodermic needle large or one for turkeys and inject straight roundup into the roots will let you know

The worst plant coming from nextdoor destroyed my fence and concrete outside cut it back to nextdoor garden but repaired the cracks looking for weed killer to stop it's growing

Cant see how cutting it at the stem kills it.

Don't put it in the trash. You are just sharing the problem. Burn any cuttings and clean your boots afterwards. Even a small piece wedged in a shoe tread can spread this evil plant.

I’ve been told not to cut it…

I see why digging it up isn't 100% effective, but is it harmful? Wouldn't digging up at least a portion of the rootball cause more harm to the plant and therefore be at least somewhat beneficial?

Why not burn it?

Here in uk i here they are dangerous for property

Hahahaha i love my knotweed i am an herbalist so i use it for medicine..i just got done chopping the root..

waste of time it will be back for for your lifetime.

This method doesn't work. Solarize it in plastic? This plant came from living on the sides of volcanoes. It's practically indestructible. It needs an herbicide applied during "the window" which is between flower fade and frost, that's when the plant will take in the herbicide and bring it down to its roots. Applying an herbicide outside the flower/frost window only kills the leaves but the roots continue to strengthen and shoot up elsewhere. You're correct that mowing is never a good idea, but cutting doesn't work either. It only encourages the roots to grow elsewhere. This is no ordinary invasive plant. Hiring experts who know about the correct use of herbicide and proper timing are the only way to manage it.

Ma’am, do you intend to do this for the rest of your life? This isn’t effective.

Lemme save you 4 minutes. Knotweed is knot a problem. All you gotta do is get some garden variety scissors, cut it into manageable portions and roll it into an expansion joint. I won't lie, the only unmanageable thing about knotweed is how high it gets you when you smoke it down. It's the highest I've ever been, my mind snapped like a carrot. You know it's pure when you see those orange flecks. Just seconds after smoking a knotweed blunt I was flying high man, I started licking walls and eating dog food. When I came to I'd blown a load in my pants and had to throw out my boxers. Put me in a state of vegetative regeneration for a week. It was well worth the sacrifice

That’s not doing anything it’ll just grow back