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Thistle Problem

Discussion in 'Pesticide & Herbicide Application' started by midgetorama, Aug 1, 2006.

  1. midgetorama

    midgetorama LawnSite Member
    from Montana
    Posts: 3

    New sod in July of '05. Unattended vacant lots on both sides with 5' tall weeds. I counted 58 thistles in the grass of the back yard yesterday.

    I believe they're Canadian Thistles. Purple flowers.

    What can I do?

  2. upidstay

    upidstay LawnSite Bronze Member
    from CT
    Posts: 1,341

    Any good broadleaf herbicide should work. Momentum, 3 way, etc.
  3. GreenUtah

    GreenUtah LawnSite Senior Member
    from SLC, UT
    Posts: 866

    add a surfactant. even though the leaf surface is very large on these plants, they do have a waxy coating that makes it tough to stick herbicide and water alone. As upidstay said, any of the broadleaf selectives will be fine at the labelled rate and a good surfactant/adjuvant/penetrant will kick the results up considerably.
  4. midgetorama

    midgetorama LawnSite Member
    from Montana
    Posts: 3


    Thanks very much. I tried a broadleaf type weedkiller once before with little results.

    This is a great site!!!

    Can you recommend a surfactant?

    Thanks again.
  5. indyturf

    indyturf LawnSite Bronze Member
    from Indy
    Posts: 1,873

    you can just use dish soap as a surfactant. another thing that will help is to step on the thistle before spraying it, this will break the skin and allow the herbicide to get inside the plant.
  6. upidstay

    upidstay LawnSite Bronze Member
    from CT
    Posts: 1,341

    Regarding th dish soap: USE PLAIN OLD IVORY LIQUID. Alot of dish soaps have all kinds of additives that can damage the plants you don't want to hurt.
  7. GreenUtah

    GreenUtah LawnSite Senior Member
    from SLC, UT
    Posts: 866

    actually, many have ph values that can neutralize your weed control. Ivory has been mentioned before as a neutral ph, but there are probably others as well. just a squirt in a pump up can is plenty, but any ag store will also have what you need in a product designed for compatibilty and not quite so much foam..lol..you have to get broadleaf herbicide anyway, so just ask while you're there.
  8. yardprospraying

    yardprospraying LawnSite Member
    Posts: 147

    If the thistle has already flowered, then they are full grown, it might be harder to control them, especially if it is dry. Definitely use the 3-way type broadleaf herbicide, the more dicamba in the product the better. Make sure you wet the plant good since they have that "waxy coating".

    If at all possible don't let them go to seed, they drop a ton of seed that can lay dormant for 15+ yrs. In Oklahoma they are on our noxious weed list. If they are growing in the ditch they either spray em or dig em up! If they are on farm land and you let them go, the state or county will spray, and send you the bill;)

    Good Luck...
  9. 6'7 330

    6'7 330 LawnSite Bronze Member
    Posts: 1,823

    Canada thistle is a hard one to control, it has such an extensive root system. It takes diligence to get it under control.Clopyralid based products like Stinger, Confront, are very effective but not labeled for residential turf.When we spot treat thistles, the applicator will step on the thistle with his foot, to break the leaf , gives a better uptake of the chemical.
  10. heritage

    heritage LawnSite Bronze Member
    Posts: 1,268

    As the big guy said,

    Mentioned products like Confront work great for Thistle. It's the Active Ingreadent "Triclopyr" you are looking for control of this spreading weed.

    Find a herbicide with Triclopyr (Amine formulation if it's above 55F air temp or Ester if below 55F ) that is labeled for the turf/residential in your area.

    Say bye bye to Thistle.


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