Discussion in 'Pesticide & Herbicide Application' started by stevebullman, Jul 29, 2007.

  1. stevebullman

    stevebullman LawnSite Member
    from UK
    Posts: 5

    Hello all, im new to this site, also new-ish to spraying. my field is tree care which i have been in for 10 years now.
    quick question regarding tordon22. I have been trying to deal with a patch of japanese knotweed for the past year now. it has had 3 doses of round up now and is still persisting....i have got some tordon22 which i read about, i'll be applying that soon. my question is, how long should it be left before it is safe for their dog to be around? the site is at their shop, they take their dog there monday to friday so if i spray saturday morning or friday evening even it would have 2 days. will this be a safe time?

  2. boats47

    boats47 LawnSite Member
    Posts: 244

    From what I understand, tardon22 (picloram, triisopropanolamine salt) is a very controled herbicide and can stay in the soil for up to 6 years. Are sure you want to use that? It is listed as one of the most persistant herbicides out there. As far as entry time to the area, read the label! Why dont you try "Confront" first, it has done a very good job controling the jap knotweed in my side yard. My oppion, is that you stay away from the stuff, but I could have the wrong chemical.
  3. stevebullman

    stevebullman LawnSite Member
    from UK
    Posts: 5

    thats for the reply. 2 years i believe is what i heard.
    i havent heard of confront. and unfortunately i dont have the label. I was given enough for the job from a company i do some work with occassionally. the label wasnt on their bottle either, i expect they had it filed somewhere.
    i was advised to use tordon by someone who specializes in invasive weed research.
  4. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 12,229

    Are you talking about the 10 feet tall tall invasive, creeps with strong rhizomes type of polygonum? Does it die after frost? May I suggest, knock it down, and start mowing it and plant grass. Apply weed killer often and keep it mowed to 2 inches in height or less. Otherwise it will probably come back from the rhizomes in the soil.
  5. Ric

    Ric LawnSite Fanatic
    Posts: 11,956


    I will second boats47 reply about Tordon being a very dangerous product. My State of Florida has ban the sale of it many years ago. I do have some Tordon and at one time used it to kill Brazilian Pepper trees. However I found it can trans-locate in the soil and can kill non target plants.

    You talk about Spraying it?? I have never sprayed it. I always used the Stump Cut method of painting the stump right a way after the cut. I use a trigger spray bottle and hold it very close while squeezing the trigger slowly. It does not take much.

    Alternatives would be Garlon 4 which while also dangerous in the wrong hands, would be a much safer product to use if you are going to spray.
  6. stevebullman

    stevebullman LawnSite Member
    from UK
    Posts: 5

    thats for your replies, its certainly given me something fresh to think about
    knocking it down really doesnt help nor will planting grass, the stuffs a pain in the i right in assuming its not a prob in the states?
  7. Ric

    Ric LawnSite Fanatic
    Posts: 11,956


    We call it Mexican Bamboo and the recommended control treatment is a total ground poisoning. So your friend's advice might not be bad. Be sure to watch drainage area for non-target plants and water contamination.

    Sorry I had to Google Japanese Knot weed to realize what it was. If you Brits spoke better English, then we Americans could understand you.:)
  8. tremor

    tremor LawnSite Bronze Member
    Posts: 1,476

    That's funny. We call Polygonum "Japanese Knotweed" here in the northeast too. LOL

    I've found that Roundup plus 2,4-D ester does a fair job but you must use a good surfactant & time it right. Too early or too late is no good. Hit it hard when it's 2-3' tall.

    Ditto all the Tordon precautions. It will root absorb into every nearby tree. Bad mojo.

    Boats suggestion of Confront might be the best bet. The technical name is clopyralid.

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