Japanese Knotweed

[davee52uk]

This has been found on one or two plots at our site and is going to be a real pain for the plotholders. This is notifiable pest in that the DEFRA has to be informed about this. The area then has to be cordonned off and treated with strong weedkiller for about three years before the land can be used again- BEWARE!!

[davee52uk]

[Robert_Brenchley]

The stuff's a menace. Birmingham city Council are really good on this, and we're well on the way to eliminating it from the site as a result, but other landlords may be very different.

[SMP1704]

Did anyone catch the piece on BBC news about knotweed this morning?

Two clips, one in Cornwall with labour intensive application of chemical down each hollow stem - which works and the other about tests using its native pest - a small beetle...tests are ongoing to ensure that the beetle does not become as invasive as the plant ::)

I have heard about the chemical down the stem - but what is it and/or is it for licensed users only???

[caroline7758]

Here's the BBC report

http://news.bbc.co.uk/1/hi/sci/tech/7531221.stm

[Baccy Man]

I have heard about the chemical down the stem - but what is it and/or is it for licensed users only???

It's glyphosate. The idea is that if it is applied in late summer/early autumn when the plant is drawing nutrients down from the top growth to the roots a large dose of glyphosate will go down intoi the root system too & cause a lot of damage as the plant will be depending purely on whatever nutrients it has stored in the roots throughout the winter. If it is more weedkiller than nutrients the odds of the plant surviving the winter are not that good.

[allaboutliverpool]

I had it on my plot and applied Glyphosate four times during the summer of 2006 and there has not been a sign of it since.

Admittedly it was not one of those forests of the stuff that you see but it was already 4 feet high when I stared spraying at 3 weekly intervals.

[lolabelle]

we have it on one or two plots the same as Davee52  its near my plot about two plots away so watch this space  >:(

[hellohelenhere]

Davee, when you say that it has to be notified to DEFRA, is that because allotments are classed as agricultural land, or something? I've just been looking at the Japanese Knotweed Alliance website, and it doesn't say anything about that, only that if you have it on your land you should get advice and deal with it quickly.

[Amazin]

I'd always thought that Japanese Knotweed was a notifiable weed i.e. had to be reported to DEFRA, but apparently not, according to DEFRA's website:

http://www.defra.gov.uk/wildlife-countryside/non-native/knotweed.htm

Here's some more info on the proposed control:

http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/10/14/eaknotweed114.xml

[fluffygrue]

On the plus side, the new shoots are very tasty, and make a good substitute for rhubarb in a crumble. :D

[telboy]

fluffygrue,
You gest of course!
This is one serious weed - like pigeons/grey squirrels/muntjak deer etal.
Needs sorting on a serious scale!

[Emagggie]

It grew under and toppled a 6ft high wall from the pub car park next door to my place. Luckily the pub rebuilt it for us and say they are treating the weed, but I'm not leaving it to them, I've got hold of some Glysophate (at enormous expense :o) and I paint it on the leaves every time I see a shoot. It seems to be working so far, but it is also on the edge of the field opposite and all around the council nursery behind us. They do absolutely nothing about it . Thank goodness it's not on my plot.

[ceres]

fluffygrue,
You gest of course!

He doesn't!  From PFAF:

http://www.pfaf.org/database/plants.php?Polygonum+japonicum

"Edible Uses
Edible Parts: Leaves; Root; Seed; Stem.

Young shoots in spring - cooked. They can be used as an asparagus substitute[55, 62, 116, 1599, 179, 183]. They have an acid flavour and can also be used as a rhubarb substitute in pies, fruit soups, jams etc[183]. Older stems and shoot tips - cooked[62, 159]. They taste like a mild version of rhubarb[K]. Seed - raw or cooked. It is rather small and fiddly to utilize. The seed can also be ground into a powder and used as a flavouring and thickener in soups etc, or can be mixed with cereals when making bread, cakes etc. The root is sometimes eaten[183]."

[Baccy Man]

There are some knotweed recipes here

You can also make Japanese knotweed wine

[davee52uk]

1. This was not growing on my allotment but was found on two plots on our allotments area.

2. Talking to committee members of the allotments society, they said they had had to notify DEFRA who then told them how this had to be treated.

3. Treatment included fencing off the area where they were growing and treating with weedkiller for two years.

[Poppy Mole]

It was growing on the edge of the pub garden where I was a few years ago,  I chopped it down & poured neat Roundup down the stems on a regular basis & after a couple of years it gave up.

[Mrs Ava]

Glad to say I have never come across knotweed before however it is in one of the gardens I tend.  I am going to speak to the home owner about it - the only thing that made me wonder if it wasn't knotweed is that I have heard about it coming through concrete, but these grows alongside a patio and has never made any attempt at spreading. 

[Emagggie]

It's even on Cbeebies in Balamoray ;D. I spotted it this morning. ;D
EJ it seems to stay put for a long time, but it's probably spreading nicely underground. You just have to be vigilant.