Japanese knotweed problems

[Yog Sothoth]

Interesting thread. I live at Norton Woodseats and there's two biggish patches of it on the embankment below the University Playing Fields, off Woodland Road, near Newfield School. It's started to spread into the woods leading to Carr Wood and Meersbrook. I rang the council but they just said "not our land mate". Might try and poison the stuff myself. I have a feeling it will eventually spread into the gardens.

Sodium chlorate ought to do it. Kills everything and persists for ages in the soil.

[Mathom]

It's getting everywhere. There's some in the trees at the bottom of Heeley City farm, and it's in the Sheaf river now, too - all at the back of B&Q and Graham and Jewsons. There's also a huge coppice of it up the side of Ace wedding cars, in someone's back garden at the end of Shoreham St, and across the other side of Shoreham St, but a bit further down, there's a garden & some garages that had loads of it in last year. If you go on the train through Rotherham, all the river banks are choked with the stuff.

[muddycoffee]

To be perfectly honest I have been noticing it for years and years. Even when I was a kid back in the 70s there it was growing on various patches of spare land where we used to play in hillsborough and I distinctly remember smashing my way through it with a stick. Some of that land now has houses on it and I don't recall seeing ant JKW there recently.

 

There is loads of it nearby but it really seems to die back quite severely in the wintertime. I am sure that it would have taken over everywhere if we had a warmer winter climate. Probably why they have such a nightmare in the westcountry.

 

 

There was a lady on a gardening programme on radio 4 who worked on a large estate in the south somewhere overrun with the stuff, and she said that they have made good progress reducing it by cutting all the green stuff off every single year and stacking it high up to dryout. I assume they must put it on a metal roof or somewhere where it can't root or blow away.

 

Another one I heard is a biocomposting company which feeds it into a hopper with a slow turning screw where the contents are heated to an extremely high temprature over a day or so, and out comes completely sterile compost for using for bedding plants etc which is rich in nutrients for growing stuff in the garden. This is the only scheme approved by the government for disposal of the weed by recycling.

[Bago]

Oh dear. Does it mean that we have an epidemic on our hands ? >.< !

I do live near one of the areas that you guys posted about. Now I'm a little bit worried. Having scanned one of the weblink, I can see that it has little flowers in the summer ? Does it mean that the seeds are lilely to spread too ?

[Yog Sothoth]

Yeah it spreads by seeds and also by rooting of broken fragments. Its home in Japan has a similar temperate maritime climate as the UK so it likes it here. Unfortunately it has NO natural enemies here, so grows unchecked. Slightly sinister stuff, and I generally LIKE plants, even the other invader, giant hogweed!

Sodium chlorate weedkiller will kill it and sterilises the soil for 2-3 years afterwards, so NOTHING will grow. Drastic but effective. To tackle a big patch needs a lot of sodium chlorate though, which isn't cheap, and you'd probably get the police round thinking you had a bomb factory set up!

Any other removal method takes loads of time and hard work, even using paraquat or glyphosate, which have to be sprayed repeatedly over 2 years or even longer.

Funnily enough, the young shoots can be cooked and eaten like asparagus. Quite tasty apparently.

There is a massive epidemic and it's time Defra put some money into a nationwide effort to tackle the stuff. Leaving it to landowners or skint councils is never even going to make a dent, and eventually it'll be destroying our gardens, then invading our homes. Ordinary citizens can't devote the money, time or effort required to stop it and if it's on neighbouring land, it's just firefighting anyway, trying to keep it off your own land.

[szb100]

Just saw this and I'd like to mention that sometimes dealing with Japanese Knotweed is not the nightmare people make it out to be.

We had about 6 ft of the stuff coming through a retaining wall. After getting the people on the other side to spray weedkiller, we sprayed our side as well and after recurring treatments and a bit of persistence it hasn't yet come back.

Woo.

[Yog Sothoth]

That's reassuring to know. Unfortunately near us there's maybe 100sq.m of the stuff getting bigger every year. I'm going to blast it with sodium chlorate. Bare soil is better than an endless knotweed forest. Eventually ordinary weeds will colonise it anyway.

[szb100]

Glyphosate worked for us. If you break the stems and pour it down the hole it helps as well.

[I1L2T3]

4 In the patch of land adjacent to Holmhust road and behind KFC

 

It extends along the side of the stream on the other side of Holmhirst by the banks of the stream behind the Big Tree. Know somebody on Fraser Crescent and it has infiltrated their garden causing some minor structural damage to walls.

[muddycoffee]

Yes that stream is in quite a deep little valley, I expect that it makes the area well protected from frost during the winter which will prevent the weed from dying back so much in the winter.

It is areas like this that everyone in the city should really be concerned about. Because unchecked it will lead to everyone's property being threatened.