Japanese knotweed

Hi,

I just moved into my new house, the neighbour pointed out that we have some Japanese Knotweed in the bottom of our garden which has come from an adjacent piece of land (not council land apparently, and nobody knows who'se it is).

So I have been reading up on this stuff, apparently it's very nasty.Anybody had success getting rid of it? Care to share your experience?

I was thinking for the ones in my garden, cut them down and pour bleach or weed killer down the shoots (no water nearby), dry out the stems and burn them.

If that works, do the same to the ones over the fence.

Advisable? Any thoughts?

 

contact your local council and ask for advice .... they normally are very helpful and may assist (for very cheap)

they will also be able to find out who owns the vacant land

 

Hi China Diapers

I deal with this stuff quite a bit, and there are two main ways of dealing with it: Cutting or herbicide treatment.

Cutting

Cut the stems when young. Dry completely. Burn thoroughly. Repeat the process in order to reduce the underground rhizome biomass. You can then also spray the stumps with a Glyphosate based herbicide such as Roundup Pro Biactive 360/450

Herbicide treatment

Don't cut, bruise or damage the plant in any way as you need it to have an intact vascular system to transport the herbicide solution.

Apply the herbicde (preferably Roundup as mentioned above) during late summer/early autumn, to the upper and lower leaf surface as well as the stems. The timing is important as during this stage it is beginning to shut down for the autumn and will quickly translocate the herbicide down into its underground rhizome.


Whatever you do you'll be looking at years of treatment before it's completely gone. I'm surprised that you were able to get a mortgage on a property that has knotweed in the garden. Most mortgage providers won't offer a mortgage if there's a sign of knotweed in the vicinity.

 

I am going to disagree with Marley and HarmonyArb, to some extent here. Bruising plant tissue DOES NOT, increase the plants ability to absorb chemicals, in fact the reverse is the actuality. Also, treating Knotweed in the autumn, because it will " quickly translocate the herbicide down into it`s undergound rhizome " is daft. Even councils have now started treating Knotweed monthly as a more effective way of treating the plant, because the plants circulation system is working all through the growing season, not just at the end of the year. As for using a Glyphosate weedkiller to treat the roots is inane. Glyphosate is absorbed through the leaves NOT the roots.

 

Disagree if you must, daitheplant - this is, afterall, a forum open to discussion. I would just like to point out a few things though, just so that China Diapers is able to take the right course of action:

This is what I was alluding to. Hence why I said to not do it.

The plant's system is running throughout the growing season and I never said otherwise. However, during the latter months, as the plant begins to die back, energy (in the form of water and nutrients) is stored in the rhizome for the plant to overwinter. Fact, not fiction. Therefore more of the herbicide product will be drawn into the root, rather than lost in evaporation/respiration.

China Diapers: I'm sure you have researched this problem well, but here are a few websites that may be of help:

• Environment Agency - Japanese knotweed
• Cornwall Council - Herbicide treatment for Japanese knotweed
• Exeter City Council : Japanese Knotweed

Hope they're of some help.

 

Thanks everybody for the responses, and the welcome.

I take all of your advice into consideration with my plan for removing the vile Japanese Knotweed from my garden.

Will update you with how I get on.

 

And as I said, you cannot treat the roots with Glyphosate, if you are any good at your job you will know that Glyphosate is biodegradable, which means, in case you didn`t know, it is inert on contact with the soil, Ergo, it is useless as a root killer. Also, you are recommending a product which is not readily available to the domestic gardener. I don`t understand your surprise at a mortgage being granted. I used to look after a garden in Lisvane, just outside Parc Cefn Onn which had a paddock full of the stuff, When the old lady died, the property, and the knotweed, sold for about a million.

 

I'm more than happy to debate the pros and cons of knotweed control methods, but I don't think it's really going to achieve much. However, you've brought up some good points that I should address:

• Roundup won't work on roots, you're right. I've amended my previous statement to what it should have said; spray the stumps.
• Roundup Probiactive is not readily available to the public, as you say. I should've mentioned this and offered a suitable alternative such as Roundup Tree Stump & Root Killer, as advised by the Roundup company themselves.
• Re: mortgages and knotweed:

1. Japanese Knotweed
2. Mortgages refused over invasive weed - Telegraph
3. Homeowner denied mortgage after Japanese knotweed discovered in his garden | Mail Online
4. Japanese Knotweed Mortgage - Wise Knotweed Solutions
5. Mortgages and Japanese Knotweed || Japanese Knotweed Removal By Wreford
6. Japanese knotweed frequently asked questions for homeowners

Hopefully China Diapers has all the information needed in order to deal with this problem and this thread needn't continue.

 

I once read a story where someone found japanese knotweed on his property and ended up getting experts to remove it .... it cost thousands, as a bulldozer was used to remove several feet of topsoil and new topsoil was added

don't know if the story was true, but sounds like a real menace

thats why I said you should contact the council ... it will not help removing the knotweed from your property and not from the vacant land where it originated from .... it will just spread back again and will eventually invade your neighbours gardens aswell

you may be lucky and the council may remove it professionally for free )especially if all your neighbours complain to the council)

 

Jeez, didn't realise I had such a serious task ahead of me. I thought the neighbour was crazy the way he was talking about it, clearly he knows more about Japanese Knotweed than me.

Interesting re the mortgages getting refused. There are only about 10 - 20 youngish plants behind our shed so maybe they got missed in the survey. They are about 1.5 meters high though so not that easy to miss.

There is a huge clump of them over the fence, big ones, they are going to go too, I just need to perfect my technique on the ones in my property first. Work to commence this weekend.

 

Are machetes legal in england?

 

I just wanted to add some encouragement. It can be done.

I had knotweed in the communal garden at one house I lived in. And it was also on the other side of a wall in a vacant piece of land. I poisoned both areas over 2 years. And won. I watered on sodium chlorate (just what my Mum suggested). I did lose a few nearby plants but it was worth the sacrifice to get rid of the stuff. I didn't bruise or bash anything I just watered it on. I treated both my garden and the vacant plot. I think I sprayed round up on any new growth as well just to weaken it when ever I saw any! You just have to be really vigilant and persistent.

Good luck.

 

The problem is Kate, Sodium Chlorate is now banned. Just about the only chemical available is Glyphosate.

 

I didn't know that! I merrily watered it on my knotweed for 2 years. I guess its just too poisonous?