Knotweed Pricing

[spence]

Hi

Looking for some advice on pricing for a knotweed job, intention is to stem inject but have no idea what to quote so any helpfull suggestions would be appreciated. Area in question is about 25 square meters. Thanks in advance

[HCR]

At 5cc per stem? £200 a day plus cost of glyphosate? There could be 500 stems in 25 square metres, so that's a lot of herbicide.

[RobRainford]

Why quote for something you have no idea about doing? Your either gonna come up short and work for nothing or find you are too expensive. Plus if you don't get all the stems you have to go back and get them. It's getting close to the time where you can just spray them now instead of stem inject.

[spence]

Thanks for the comments. The majority of advice Ive been given and have read says stem injection is best late summer (august). Any comments on that one?

[HCR]

I've found it works well at any point in the growing season.

 

When you say stem injection, what exactly do you mean? Injecting into intact stems or slicing them off and 'dosing' the remaining portion?

 

I found the former has a much higher success rate.

[spence]

Hi

intend leaving stems intact if possible, did hear that injecting in 2nd and 3rd section gives the best results but that could be an old wives tail!

[HCR]

Hi

intend leaving stems intact if possible, did hear that injecting in 2nd and 3rd section gives the best results but that could be an old wives tail!

 

Funnily enough I read just the other day that someone thinks injecting between the 1st and 2nd nodes gives the best response. I'd always heard below the 1st before that and can vouch for the results (close to 100% crown death at 5cc per stem). Stems too small to inject need to be sprayed at the same time though.

 

One thing you need to watch out for is the maximum application per hectare limit, which can creep up on you quite quickly.

[RobRainford]

Glyphosate is usually approx 5l/ha so you need 1000 stems to hit the limit at 5ml/stem. We usually inject within a couple inches of the base.

 

HCR: if you sliced off the stems you'd have to dispose of it. Leaving it there just makes a problem.

[RobRainford]

Thanks for the comments. The majority of advice Ive been given and have read says stem injection is best late summer (august). Any comments on that one?

 

Late summer and into autumn is the best time for any treatment of this weed as the upper parts of the plant begin to retract and spraying the tops will mean the chemical is absorbed easier. We got less control of we sprayed earlier in the season.

[Hill-Billy]

I had Japanese Knotweed in my garden, used Roundup successfully over two seasons and the ground wasn't contaminated for two years like the glyphosphate leaves it. No injecting just thorough spraying the top and bottom of leaves. You can buy the stuff in concentrate from any good farmers' supply.