Japanese Knotweed in my garden affecting the sale of my flat :(

lessonlearned

Well vinegar or coffee are certainly worth trying, probably less risky than introducing non native species of insects which as Elantan points out could cause more harm than good.

Davesnave

Yorkie1 wrote: »

I can't remember when he did the treatment, or how often - but it was gone within a year and has not returned.

Autumn, when the plant is reabsorbing the nutrients in its upper parts and transferring them to the deeper root structure for overwintering.

Other methods, like spraying, just scratch the surface, but will still work long term if the person is persistent.

Human beings aren't always good at being consistent in their approach, though!

Mojisola

donfanatico wrote: »

Interesting:

http://howtokilljapaneseknotweed.blogspot.co.uk/

I don't think 9 days was long enough to show results that could be replicated on plants growing in the ground.

I think that the vinegar and coffee that killed small, pot-grown knotweed wouldn't have anywhere near as dramatic an effect on a plant with a big, deep root system.

The 9 days also wasn't long enough for glyphosate to finish working.

If you do an experiment and find that the method that is used all over the world to kill a plant doesn't work in your test, you should come to the conclusion that your test was poorly designed.

RAS

Davesnave wrote: »

Autumn, when the plant is reabsorbing the nutrients in its upper parts and transferring them to the deeper root structure for overwintering.

Other methods, like spraying, just scratch the surface, but will still work long term if the person is persistent.

Human beings aren't always good at being consistent in their approach, though!

The worst thing you can have is some birk who pulls the stuff up which means there is nothing above ground to treat.

You need to dry and burn the cut stems (and dry them on plastic to stop them rooting.

Our plague probably resulted from a fencing contractor who dug into one patch and spread it all along the fence line.

Ivana_Tinkle

The stem treatment method works amazingly well - speaking from experience! Our local council is happy for you to take JK stems to the tip, as long as they're double-bagged. IMO it's not that JK is difficult to treat - it's more that it's tedious work and people just don't bother to do it properly, plus there's LOADS of misinformation and hysteria around. Some bloke down the pub will tell them just to cut the stems back, or to try and dig it all up, so they do that for a few years, watching it get worse and worse...

GM11

we have this stuff tho we are lucky thats its 100 feet from the house and our buyers dont need a mortgage, the very best stuff to kill it is a chemical called proclam found in a herbicide called TORDON, way more power than glyo based stuff. you need a gardner with a license to use strong herbicide as this stuff isnt over the counter. Its pricey at around £400 per 5ltr but 5 ltr will do 2 hectares!
best used mid summer then early autum, personally i would go for stem injection, TORDON normally kills it in a season maybe 2 tops. As a side note it was apparently used in the vietnam war in places where agent orange didnt get the job done :eek: and was known as agent white. anyway hope that helps and dont panick it is a plant that can be eradicated the real problems come when you have it under foundations, in all honesty the histeria with mortgage companies over it is rediculous

witchy1066

it makes me wonder how any houses sell,
every house we have looked at in South Wales has JK, and most of the council land is rife with it ,

another thing about JK , it has a distinctive pleasant smell

GM11

the main problem with getting rid of it is motivation and human nature! i say this because it reminds me of something similar...friends of ours moved to scotland about 4 years ago, near to where we are moving (glenluce area) the area has a big problem with Rhododendron, our friends have around 30 acres and its smothered in the stuff! it's so bad in some parts of scotland (including glenluce) you can get pretty good grants grants to get rid of it, the catch is you have to do the work first then prove after 5 years you have completely got rid then you get the money. Our friends looked into this and to be honest eventually decided they couldn't be bothered with all the hassle and paying out first.... so they left it!!
Then skip forward a couple of years to about two years ago and said friends got a shiny new biomass wood chip/pellet boiler, they soon realised how much theese beasts can consume in wood and the cost of pellets was about £250 ton, untill one day someone pointed out to them that as long as you dry it well Rhododendron burns great!! skip forward to present day an our friends have almost no Rhododendron on there land and thriving business supplying Rhododendron woodchip and have free hot water and heating! so i guess JK will stay a problem untill a way to make/save money is found for it

moneyistooshorttomention

donfanatico wrote: »

I will try on a section and see what happens

Go for it and keep us posted on the results.

If you want to do a larger-scale trial, then maybe contact a public relations type person at a suitable vinegar-manufacturing firm (eg Sarsons) with the idea and see if they might sponsor you (by providing some vinegar for free).

After all, it would be a lot of extra custom for them if it worked....

If you decide to try a coffee trial too, then I wonder whether used coffee grounds might be worth trying and I believe St*rb*cks give away unused coffee grounds for using on the garden.

moneyistooshorttomention

witchy1066 wrote: »

another thing about JK , it has a distinctive pleasant smell

....for identification type purposes...what "sort" of "pleasant smell" would you say?

Is there anything it reminds you of that we would commonly come across elsewhere eg roses, fresh-baked bread, lemons, whatever.....(just to give some examples of pleasant smells that I thought of instantly off the top of my head).

At what stage is this smell there, ie all the time, just when its flowering, etc?