Japanese Knotweed

[peds]

Yeah I know, knot exactly a tree, but you guys are just so bloody clever I know you can help with this.

 

I've just inherited the use of a polytunnel which has lain dormant for a couple of years, and a nearby clump of Japanese Knotweed has started to poke through the ground in places. It's not too bad, but the problem will only get worse, obviously. I'll try and get a couple of photos tomorrow.

I've got plans to move the tunnel in the future, maybe next season, maybe the year after... but for this year, what can I do to minimise the problem? I'm wary of cutting the stems out, but I'd much rather keep the ground that I have available instead of putting in raised beds or benches after putting down sheets or slabs or something, as I hope to move the tunnel in the future. How much of an extra problem am I creating by just cutting the stems now and pretending they don't exist for the rest of the season?

 

Thanks for any advice dudes.

[openspaceman]

38 minutes ago, peds said:

Logically this does seem like it would be the least damaging to an area that I'd like to be planting vegetables in as soon as possible, but what if - and please, don't laugh here - what if I'm morally-opposed to glyphosate? And, more specifically, sticking to an organic growing system?  

How big an area?

 

You could dig it up, sift it out and burn it, just make sure you don't move any bits off the affected area. Soil sterilisation with steam is also a method.

[Toad]

40 minutes ago, Toad said:

Just glyphosate, or all chemical herbicides? There's probably alternatives.

Really ought to read more better.

 

I'm not sure about organic alternatives. Maybe burn the stems and shoots off whenever they appear? It's tricky to get rid of with herbicides, so I think you'll be in for a fight.

[peds]

Oh, but I like a challenge. Maybe I'll try homoeopathic remedies, invocative chanting and yoga instead of the tried-and-tested chemicals. Kinder to the bees. 

 

Fire could be a good idea though, I'll definitely look into that. 

 

[Gary Prentice]

27 minutes ago, Toad said:

Really ought to read more better.

 

I'm not sure about organic alternatives. Maybe burn the stems and shoots off whenever they appear? It's tricky to get rid of with herbicides, so I think you'll be in for a fight.

I don't think that burning is particularly effective, as it originates from volcanic regions. Anecdotally a friend dug some of the roots up, threw them on his huge Nov 5th fire, only to discover new stems appearing at his fire site the following year, despite there never having previously been any JK in that part of the garden previously. 

[daveatdave]

you will not dig it out as it can go down 10ft try Gallup pro but it could take 3 years to kill it off 

[Woodworks]

We had lots of it here and would just pull out what was seen. Never dug or used pesticides and all clear for many years now. 

[Haironyourchest]

10 hours ago, peds said:

Logically this does seem like it would be the least damaging to an area that I'd like to be planting vegetables in as soon as possible, but what if - and please, don't laugh here - what if I'm morally-opposed to glyphosate? And, more specifically, sticking to an organic growing system? 

If you ate bread this morning, you ate glyphosate! They spray is on cereal crops to stop the growth and essentially kill the plant, for drying on the stalk before harvest (I don't like it either, but we've all been eating it for decades) Injection is preferable because knotweed is such a hardy plant, leaf spraying may just kill the upper portion of the plant and not get absorbed far down enough to kill the rhizome. If the plants are a first year infestation from imported nodes, then the rhizome may not have developed much, and maybe just painting the leaves with a soft brush will kill it. If it's been around more than a few years, you should inject. Regular concentration roundup prep, injected into the centre of each and every stalk, preferably at or just after growth peak, near the ground. Use an agri syringe and big needle, and cut or sleeve the needle so only 5mm or so is bare, so you can press it right onto the stalk without the chance of it going clear through the other side - will speed things up. Don't know what amount to inject, sure it's easily found by googling.

[nepia]

46 minutes ago, Haironyourchest said:

If you ate bread this morning, you ate glyphosate! They spray is on cereal crops to stop the growth and essentially kill the plant

Many years ago I worked on arable farms and I've never heard that one.  Roundup on rape yes, but never wheat, barley or oats.  Am I just behind the times?

 

As for eating glyphosate you may be ingesting (allegedly harmless) breakdown products but you won't be eating glyphosate.  That's a bit like saying you'd be eating fungicide because Farmer sprayed the growing crop against Wilt.

[openspaceman]

24 minutes ago, nepia said:

Many years ago I worked on arable farms and I've never heard that one.  Roundup on rape yes, but never wheat, barley or oats.  Am I just behind the times?

When I worked on a mixed farm we used gramoxone to dessicate prior to combine ?

 

FOE claim 78% of OSR is dessicated with glyphosate and it appears to be cleared for all crops whether food or industrial.

24 minutes ago, nepia said:

 

As for eating glyphosate you may be ingesting (allegedly harmless) breakdown products but you won't be eating glyphosate.  That's a bit like saying you'd be eating fungicide because Farmer sprayed the growing crop against Wilt.

FOE quote

" For example, the increased use of
glyphosate as a desiccant on UK wheat crops has been linked to increased glyphosate
residues in UK breadx ."

 

[openspaceman]

10 hours ago, daveatdave said:

you will not dig it out as it can go down 10ft try Gallup pro but it could take 3 years to kill it off 

At the olympic park it all soil was excavated and reburied below 4m in plastic lined cells, It was probably not successful because of the scale and poor implementation.