Japanese Knotweed

Hello, I am a new member and an absolutely novice gardener looking for some help. I recently bought a house with quite a bit of land upon which I have numerous quite large clumps of knotweed.

The land I have is a mixture of woodland, garden and a quite large walled garden. There is knotweed in varying clumps in all 3 areas and I would like to get rid of it. I have read quite a lot about different ways for getting rid of it and my plan was to start in spring next year by burning the old growth and pulling up new growth then treating with round up.

My question however is can I do anything between now and the spring that will help? It's in flower now but will start dying off soon so is it too late to do anything with it now?

Thanks in anticipation.

Regards

D

 

Welcome to Gardeners Corner

If you do a search on here there's loads of threads about it, but this one is one of the more promising ones,

http://gardenerscorner.co.uk/forum/threads/knot-weed-terror.37957/page-3#post-528824

Probably be a waste of money trying to spray it at this time of year, glyphosate only works when the plant is actively growing.

Nothing wrong with burning it over winter, but check out the threads about it being controlled waste

 

Hi, Sorry to hear about the Knotweed, from what I have read, I would not waste any time
in trying to get rid of it............you might not have it bad, but it can be known to devalue
a house.

http://www.dailymail.co.uk/news/art...ese-knotweed-growing-council-land-garden.html

This link may help as well.

http://www.environment-agency.gov.uk/homeandleisure/wildlife/130079.aspx

 

Hello and welcome.

I'm not in any way an expert on knotweed, but in general terms, I'd advise cutting off the flowers and burn them. After flowers, you get seeds. I don't know if knotweed can spread by seed in the UK climate, because I know too little about the plant, but in any case I wouldn't want to give it that opportunity.

 

Welcome to Gardeners Corner Dunny, glad you found us. There are lots of great people here who know so much and are willing to give good advice,
enjoy,

Jenny namaste

 

Welcome to GC Dunny...there was an interesting piece on Countryfile tonight about Knot Weed....try and catch it on i-player if you can

 

About 38 minutes in

 

Thanks for the link/time slot Ziggy.
I wish BBC would not keep juggling about with the time the programme starts.Was eating dinner at 6.20 last night 'cos I thought it would be at 7pm.

 

Thanks for the welcome and the links everyone.

Clueless1 - as I understand all of the Knotweed in the UK are female and don't grow from seed.
Loli - coincidentally I did see the piece on Countryfile and was hoping they were reporting on the success of using insects to combat it but alas it wasn't particularly informative.
Shiny - the seller did confess there was some Knotweed but they said it was limited to a certain place but it is more widespread than what they have suggested.

I think the best plan of action, based on what I have read, is let it die off now and turn to stalks. Then survey the land and identify where all the patches are, maybe even cordon them off so they are easily identified. Then, in the spring allow some early growth then cut and inject with a strong Glyphosate. Repeat 2/3 times throughout the growing season. Keep doing this until its gone.

I dont think there is anything I can do right now to weaken the growth for the new year?

Anyone know what the strongest Glyphosate I can buy?

Thanks

D

 

You could slice a black polythene membrane into the soil over it, it wouldn't do much while its dormant, but when it wakes up in the spring it won't be getting light to photosynthesise, so it'll have to use the energy in its roots which would weaken it.

If you get the concentrate you can make that up to the strength you want.

 

I would be inclined to inject now. less effective than an application made when it is growing, but I would suggest you throw everything at it until it has gone, even if some of the Ammo you let loose won't be 100% successful.

I would also pursue the seller. It clearly is not in the small clumps they implied, and the stuff is highly likely to spread massively, and may well come up under (and then through) concrete and so on.

if your neighbours have it then killing what you have on your plot will only be part of the battle, they need to kill their's too for it to be eradicated from the area - otherwise it will just re-appear under the fence sooner of later.

Pretty sure there is some info on using Glyphosate on Japanese Knot Weed on Monsanto's site about Roundup (the page I am thinking of lists a number of pernicious weeds, and the best time/method to use Glyphosate/Roundup on them - if you don't find it give me a nudge and I'll see if I can find it)