Hiya

Has anyone had any experience in dealing with Japanese Knotweed?

We've just had the survey back from a house we are meant to be buying in Sharrow/Nether Edge area, and the results are putting us off - severe roof spread (dealable), minor damp/rot and Japanese Knotweed in the garden, plus overvalued by 10K!!!

I've done a bit of digging around on the web it this 'weed' looks fairly serious.

If you have had any experience with it, please can you tell me of your experience? Any thoughts appreciated,

Tigs

Dealt with some whilst working with BTCV many moons ago, and the process was horrendously long and hard.

This link will give you some idea what the thing involves.

http://www.sarplc.com/ecology.html

Hope it helps Tigs:thumbsup:

Through work i believe the background is that the Knotweed was popular in the 70's when people planted the stuff. Admittidly the stuff looks ok but it doesn't stop growning and is uncontrollable.

It will grow through anything!

The choice is either to dig down to the roots (maybe over a metre!!) or kill it with several sprays over a year or two. Good luck!

and what's worrying is that a simple walk along the canal or river can leave anyone's garden infested. Just a one inch piece of the stuff in the mud on your boots can be transfered to any piece of land and it will - if conditions are right - root and shoot in weeks. You'll think you've got an interesting plant, and by the time you recognise it, it has taken hold. Nasty stuff indeed!!

Guys

Thank you very much for this.

After your comments and my research, I'm pretty much decided - I think that we're going to back out. It wasn't our ideal house, stretched our finances, has structural issues and this awful weed has just about capped it off!!!

Bugger - back to house-hunting!!! At least we've nearly completed on ours!

Thanks again,

Tigs

Off the top of my head, it was imported into this country in 1826 as a decoractive plant.

Planted in Kew Gardens, and within about 2 years had done unprecented damage to other plants because of it's aggressive nature.

Not all bad though.

I have a friend of a friend who has mixed a solution that does kill the stuff(apparently)

I have knotweed in my front garden and am letting it grow so I can try this amazing mixture.

If it does work, I might market the stuff!

What does knotweed look like is it like a vine with white bells i think i may have it in my garden,

Originally posted by nikita
What does knotweed look like is it like a vine with white bells i think i may have it in my garden,

Google it!

If its not weed what is it?

Originally posted by nikita
What does knotweed look like is it like a vine with white bells i think i may have it in my garden,

nikita, that sounds like convolulus, which is classed as a weed and very difficult to get rid of too ... although it's very pretty really, it strangles other plants and the pollenators it seems to attract are flies! There's another variety too with pink and white bells.

If you leave even a little bit of root behind back it comes!! If it's tangled around your other plants, you may have to "paint" each piece with weedkiller ... it'll take a long time, sorry to be bearer of bad news :(

Or you could just enjoy it for its beauty and leave it be ...

http://www.devon.gov.uk/index/environment/natural_environment/biodiversity/japanese_knotweed/whats_the_problem/jk_and_the_law.

I googled it just to see what it is and found it's controlled by law.

There are loads of sites in sheffield 8 with Knotweed Growing, especially near water. It is quite alarming, I read once that the council have a policy over it but I wonder if they are taking it seriously enough.

There is a house on Chesterfield road right opposite Matalan/Dixons which has a huge bush of it. At least I think that's what it is..

1 Little London road opposite the Old Wardson tools factory and all the way along from the railway bridge, it's spreading!
2 House on chesterfield road opposite matalan
3 In the bushes on the dale on the RHS before the club
4 On abbeydale road where an old club used to be and there are huge railings with damage where a tree fell down 6 months ago.
4 In the patch of land adjacent to Holmhust road and behind KFC

Also there used to be some Giant Hogweed near the A6 near Buxton, and it was truly massive like a tree. I don't think I have ever seen any in sheffield.
Another place I saw some was on the norfolk broads next to the stracy arms pub.
I have heard that you get a real bad rash if you touch it or get any sap on your skin.
I can think of a few celebrities who I would like to force feed some to at gunpoint! :hihi:

I've eaten Japanese knotweed, the stems are not bad when steamed or boiled for a few minutes and served like asparagus, with marge on.

Apparently slightly older stems can be used to make a rhubarb-like jam by peeling and boiling the sour rind with sugar and pectin - I don't fancy that.

Venger - Be careful if you have some on your land as you can be prosecuted by the Environment Agency for 'allowing it to grow', whatever that means. Mind, seeing as plain weedkiller can wipe out leylandii I'm sure your 'product' will work.

I've been looking for it on the way home as I've seen it in loads of places and I'm sure I saw some growing under a fence at the Bramall Lane ground. I think there was also some near the student flats nearby.

I'm betting that bamboo will be the next menace. Loads of people have it in their gardens but don't realise you ought to grow it in a pot sunk in the ground as this too can form rhizomes which can come up 10-30 feet away.

Giant Hogweed is amazing, it's so tall, and you hardly ever see it now apart from at the side of train tracks. Apparently kids used to make pea-shooters out of the stems and end up with scabby faces. :hihi:

Venger,
I have heard programmes on the wireless about the millions of pounds they are having to waste in the west country, to stop JKW. And it seems that weedkiller and poison seems to kill of all the green stuff but the underground stuff seems to survive.

Also you cannot put the green stuff into your bin because it goes mainly to landfill, which would cause it to regenerate. You have to incinerate to kill it in a furnace.

The contractors on the building of the new Westfield School are dealing with JKW. There is an area of land more or less facing Direct Cars which is fenced off and has clearly been treated. Can't remember what the Co is called but the sign says that they are specialists in clearing contaminated land.

Supposed to be persistant stuff, take a look at this rather scary link for pictures of it growing up through peoples floors, walls, tarmac etc!
http://www.japaneseknotweed.co.uk/pages/swep-article.htm

I noticed loads of it on the bank on the LHS at the side of Baslow Road near the lights at Totley as I came in from Derbyshire yesterday. Looking at the street map today it is close to the River Sheaf.
This is a worry as it could suggest that the river is spreading it across the city.

Thanks a lot guys, we decided to back out due to the knotweed, roof spread and overpriced property! We've looked at some other houses today, and I've been keeping a careful eye on strange plants!

Originally posted by nikita
What does knotweed look like is it like a vine with white bells i think i may have it in my garden,

That sounds more like bindweed. Still difficult to get rid of, as the smallest piece of root will flourish, but a good systemic weedkiller will work. As well as growing everywhere, it can throttle other plants as itgorws up them.

Regards

Tazz

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.

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.

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.

Never even heard of this! Will keep eye out for it now as im buying a house soon!!! Soccermon, you link doesnt work, would be good to see the pics though! x

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 ?

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.

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.

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.

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

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.

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.

Sheffield seems to be particularly bad for it. I come from Pudsey between Leeds and Bradford, and that area isn't nearly so badly infested. It's everywhere down here!

Coming back to this, does anybody know what's the best time of year to spray the stuff? I've been slashing it down and using sodium chlorate on it, but it struck me that it might be better to spray its young growth in spring, when it's only a foot or two high, and after it's used up some of its reserves overwintering.

don't get it mixed up with bind weed. That is fairly similar in appearance but far less aggresive.

No, I know bindweed (Calystegia?). This is 12 feet tall, 2" thick, unmistakeable. Evil.