Weed Killer How long in the soil?

[Frederick]

I have a difficult situation in that last year my neighbour poisened  huge Stags Horn trees in her garden.  I have had a tree die back all the leaves fell from it  although  after I pollarded it this year it looks like its trying to make leaf. My neighbour on the other side has an orchard  alongside me and one of his Peach trees died and he cant understand why. This year I have hibiscus and other shrubs we have bought in the last 3 or 4 years that have died  . I now suspect that underground seepage through the water table as we are on a slope is moving this poisen slowly from her ground down hill under our gardens ... I cant proove it  and my neighbour who I get on with was not the one who did the work to get rid of her trees .I dont know what was actually put on the roots but it must have been strong ..If I say what I think is happening and it is not .then I am looking like a trouble maker and will offend my neighbour ... If I am right then all hell breaks loose  between my French neighbours who at this time I dont think have worked out yet what has happened ...Has anybody any idea how long weed killer can stay on the ground active ? Stuff that acts like like Roundup .

[cooperlola]

I do know that it's recommended that land isn't grazed for 6 months after using Roundup (even though it makes claims to be "pet" safe) so I guess that's how long they estimate it affects plant life. There are plenty of forum users who know much more about this than I. However, can't you get a soil test done, before taking drastic measures and upsetting anybody?

[Frederick]

Cooperola I have no intention of upsetting anybody my interest now is in knowing when i may be able to replant shrubs in the hope they will not die . Perhaps best to leave it to next spring ?

[cooperlola]

Oh sorry - I didn't think you would it's just that I reckoned a soil test would prove one way or another if there were nasties about without having to involve anybody else. 

[Frederick]

Thanks for that I will get one of the tester kits ...I was not aware they would react to any nasties I thought they just let you know what kind of soil you had ... I will do a test .. I am keeping the neighbours in the dark re my suspicions !

[cooperlola]

Whether a standard off-the-shelf kit would tell you I don't know (it may just show acid/alkaline balance?)  In the UK DEFRA would do soil tests (I got one done when I first had land in the UK and wasn't sure if it was safe to graze my ponied on.)  I don't know what the system is here.

[Grumpy]

Roundup (active ingredient Glyphosate) is a translocated herbicide that kills the roots of the treated weed species.  The constituent parts break down on contact with the soil after 5 days so it is extremely unlikely that this herbicide is your problem.

There are other herbicides that persist much longer or another possibility is that spray drift on the day of spraying may have affected your plants.

As for grazing it is generally safe to graze after 5 days if using a low dose of Roudup to susceptable weeds or 10 days for tougher weeds.

Grumpy

[Théière]

[quote user="Grumpy"]Roundup (active ingredient Glyphosate) is a translocated herbicide that kills the roots of the treated weed species.  The constituent parts break down on contact with the soil after 5 days so it is extremely unlikely that this herbicide is your problem.

Grumpy
[/quote]

From the other thread on Roundup being banned in France, It seems that Roundup does not breakdown on contact with the soil and that is why the French recently fined Monsanto in court.

http://www.completefrance.com/cs/forums/2083780/ShowPost.aspx

[andyh4]

I am not familiar with stag horn trees, but trees suggests something has been used that is a lot, lot stronger than Roundup.

Roundup is not generally used for trees.

And Thierry is right, Roundup is a lot worse than its propaganda would have the world believe.

[Frederick]

http://www.google.com/imgres?imgurl=http://www.all-creatures.org/pica/ftshl-sumac-sh-01a.jpg&imgrefurl=http://www.all-creatures.org/pica/ftshl-sumac-sh-01a.html&h=894&w=771&sz=80&tbnid=a7QsynG5_-7IKM:&tbnh=146&tbnw=126&prev=/images%3Fq%3Dstaghorn%2Btrees&hl=en&usg=__go6S1GSfhNfVezneAh75Gl6Cchc=&ei=7-bqS4evM4_u0wTgteXRDA&sa=X&oi=image_result&resnum=6&ct=image&ved=0CDMQ9QEwBQ

 

This is the kind of tree...I now believe what was used to kill them was applied to roots...Maybe watered in ?...the shoots that used to come up on my side even in our lawn have not appeared this year..  whatever was used its certainly done for it !.

[Grumpy]

It breaks down int its constituent parts which may persist but not as an active weed killer.  We used it for 30 years in the Forestry Commission and I've used it for many years at home.  Weeds will grow back in the treated area when new seed germinates so there can't be any active long term persistance and no build up either.  From the sound of the original posting on this thread the pattern of damage doesn't fit with persistance of this herbicide but rather of spray drift.

Grumpy