Japanese Knotweed in Nunhead

[Rianoo]

Knotweed requires slash and burn. It can grow from a "severed both ends" cutting milimetres in length. Injection does not work all the time. George 74 is correct that it needs containment and it is probably the best survivor of the plant world as it would seem it defies the need for photosynthesis and can continue growing without a root structure. I have some in my garden but I remove all growth beyond where I would like it. At some point I have to replace the fence panel it seems to like and then I will burn the soil using paraffin then remove the ground and replace with top soil. It is extermely invasive but containable and should not be allowed to spread. As for bamboo...........put it in a strong container and not direct into the ground.

[benmorg]

Rianoo Wrote:

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> Knotweed requires slash and burn. It can grow from

> a "severed both ends" cutting milimetres in

> length. Injection does not work all the time.

> George 74 is correct that it needs containment and

> it is probably the best survivor of the plant

> world as it would seem it defies the need for

> photosynthesis and can continue growing without a

> root structure. I have some in my garden but I

> remove all growth beyond where I would like it. At

> some point I have to replace the fence panel it

> seems to like and then I will burn the soil using

> paraffin then remove the ground and replace with

> top soil. It is extermely invasive but containable

> and should not be allowed to spread. As for

> bamboo...........put it in a strong container and

> not direct into the ground.

I've noticed that knotweed has a tendency to grow out from under walls and fences. It seems to like boundaries, where it causes the most hassle to all concerned.

It isn't superhuman though - it has several definite weaknesses. It can't set seed as all the plants are female clones - there is no male knotweed in the UK to spread pollen. The bit you need to kill - the rhizome - cannot survive without sending shoots above ground to photosynthesize, so you can easily find the rhizomes just by waiting for the shoots to appear in spring. It takes a few years of spraying to kill it completely with glyphosphate, but can be done, whether you inject or spray.

If you cut it dig it up, you then have controlled waste problem to deal with. It's simpler just to leave it in the ground and then let it rot back after it's dead.

[KidKruger]

I am doing this this weekend. Glyphosphate I presume comes in many brands ?

[Rianoo]

The only problem there is that you assume it will die. It starts life underground where most plants are above with roots below. Glyphosphate has low toxicity for other plants but unproven on other life. It is only a controlled waste problem if you do not burn it - no need for injection or spraying of chemicals. Plus dig it up before the BBQ then you can kill two birds with one stone.

[benmorg]

KidKruger Wrote:

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> I am doing this this weekend. Glyphosphate I

> presume comes in many brands ?

Roundup probiactive is the best one for knotweed but they will all work. If if rains after you spray you'll need to spray again. Try and get the undersides of leaves so it gets into the stomata.

[benmorg]

Rianoo Wrote:

-------------------------------------------------------

> The only problem there is that you assume it will

> die. It starts life underground where most plants

> are above with roots below. Glyphosphate has low

> toxicity for other plants but unproven on other

> life. It is only a controlled waste problem if you

> do not burn it - no need for injection or spraying

> of chemicals. Plus dig it up before the BBQ then

> you can kill two birds with one stone.

The problem with trying to dig it up is that you might leave behind fragments of rhizome in the soil. The only way to kill those is to get a systemic herbicide like glyphosphate into the plant from the parts above ground. Otherwise, you have to excavate the whole area to a depth of several metres and then sieve all the soil and remove any fragment of plant matter bigger than a few millimetres wide (all of which has to be disposed of at a hazardous waste site).

Glyphosphate is effective against nearly all plants but it degrades quickly in the soil. If it doesn't reach all areas of rhizome then the unaffected areas will grow back next season, but there will be much less knotweed each year and eventually none left.

[Jeremy]

KK - I guess buy one of the concentrates so you can make a nice strong solution. The stem filling method really will work faster... and also protect your hedge.

[The Minkey]

(From memory) The thing about knotweed that makes it such a bugger - apart from its ability to regenerate and multiply from tiny cuttings - is that the rhizomes can lie at a depth of 9ft and extend to 20ft before resurfacing. It's incredibly invasive. Be careful to protect yourself as advised when using glyphosate in the form of Roundup as it has a dodgy rep.

[werdna101]

-- moved topic --

[lousmith]

> The only problem there is that you assume it will

> die. It starts life underground where most plants

> are above with roots below. Glyphosphate has low

> toxicity for other plants but unproven on other

> life. It is only a controlled waste problem if you

> do not burn it - no need for injection or spraying

> of chemicals. Plus dig it up before the BBQ then

> you can kill two birds with one stone.

Attempting to dig up Knotweed rhizome will dramatically increase the number of viable heads, which will cause a much bigger headache in the future. However meticulous you think you are being at removing all subterranean traces of the plant it will re-surface ten-fold. Same goes for strimming.

I tried to dig an exclusion trench about two feet deep and the same wide to prevent knotweed from invading from next door garden. It has since proliferated with small, tenacious little bu**ers, all over the area dug over and even encouraged new growth in my lawn beyond the trench.

Best to inject/ spray twice a year, first time about now and again just before die-back in the autumn.

New growth from trying to dig it up will be numerous small stems which will be hard to inject. Much better to tackle the mother ship when it is at the height of its vigour so as to ensure effective translocation of the herbicide to the rhizome extemities. I hate the thought of using herbicides, but the alternative is to succumb to the weed!

[KidKruger]

Where locally can I get Roundup probiactive (is that the concentrate ?) ??

I'm on a mission this weekend.

That and the moths.

[Jeremy]

Not sure about that specific brand.

But I know that you can get Bayer "super strength" glyphosate sachets from Homebase and B&Q, and you obviously mix that as strong as you like.

[KidKruger]

Thanks Jeremy, will lookout for those.

[bonniebird]

Vanessa Feltz did a whole talk on Japanese knotwees this morning on 94.9 it sound a real pain

[Jeremy]

Japanese Knotweed AND Vanessa Feltz? Sort of a double whammy, isn't it.

[red devil]

Some general info on eradicating the scourge of Vanessa Feltz Japanese Knotweed...

http://uk.finance.yahoo.com/news/plant-could-cost-home-101756824.html

[*Bob*]

For a killer plant of doom that's been around for over a century, you'd expect the whole of the UK to be submerged in 25ft of knotweed with only chimney pots poking out of the top and people gasping for air.

It's been a mortgage pantwetter but that's starting to relax now. What's everyone supposed to do? The stuff is all over the place when you start looking for it - and gardens are so close together it's often impossible to deal with without a concerted effort.

There's ongoing research to find an easier way to get shot of it - liable to come to fruition sometime soon.

[SebsC]

http://www.dailymail.co.uk/news/article-2358599/Alien-eating-garden-home--And-dont-dare-try-kill-dreaded-Japanese-knotweed.html