Discussion in 'Pesticide & Herbicide Application' started by BRIAN GALLO, Sep 4, 2001.


    BRIAN GALLO LawnSite Senior Member
    Messages: 282

    I have a question about Round-up, Spectracide, etc. grass & weed killers. I use these in and around my customer’s beds to keep weeds down in the mulch. I’m always careful and try to pinpoint the weeds with no overspray. I’ve never had a problem until recently one of my customers started loosing some older well established shrubs in beds that I treat. Now these were big shrubs (about 4 feet dia.) and I know I didn't overspray them, however I did spray some weeds around and beneath them. Is there a possibility I could have killed them? They say that stuff neutralizes in the soil but now I’m wondering. If you get some spray on the woody crown of a shrub is that enough to kill the plant or does that stuff only work through the leaves?

    B’s Lawn Service
  2. awm

    awm LawnSite Gold Member
    Messages: 3,354

    to be honest i cant give you a sure answer except to say if there was leach into the root system ,ive never seen roundup do this . i cant say that about spectricide. i use it but have wondered at times if it was as safe as roundup.nuff said
  3. UrbanEarth

    UrbanEarth LawnSite Member
    Messages: 142

    Roundup must contact the leaves or roots to be absorbed. Since it does netralize with soil contact, I do not see this as being an issue. How was the shrub affected? Was the entire shrub affected all at once, or were small areas affected first? If you hit the target with some overspray, the results should be small affected areas, not the whole plant. I would also say that from the size of the shrubs, you would have to deliberately spray them (and possibly with repeat applications) to kill them.
    That was the Roundup, Spectracide I have never used, so can't say much about that.

  4. Scraper

    Scraper LawnSite Bronze Member
    Messages: 1,656

    Brian...Where in PA are you? It could be possible that they succumbed to the high heat and dry weather we've had in this area. Could also be from overwatering. Too many variables to give you a definite answer except I don't think your roundup use could've caused this damage unless you drenched the entire shrub.
  5. plymouthvaliant73

    plymouthvaliant73 LawnSite Member
    Messages: 167

  6. wallzwallz

    wallzwallz LawnSite Senior Member
    Messages: 361

    I think we have an answer, i have never used spectricide, good thing too:D
  7. Fantasy Lawns

    Fantasy Lawns LawnSite Bronze Member
    Messages: 1,912

    Spectracide (Diquat Dibromide) interferes with cell respiration, the process by which plants take in oxygen, that’s why it works faster than Round Up … also contains small amounts of a toxic chemical (EDB), like any chemical one should know what they are using BEFORE using it ….make sure to wear Eye Protection …. this stuff is not good for the eyes …..effect comes days after even if you splash clean …but we don’t use this stuff as I find Round Up more effective in the long run and when looking for quick kill we use Scythe

    Round Up (Glyphosate) stops the production of some enzymes, which in turn prevents the plant from producing an amino acid essential for plant growth (that’s why it take so long) is only effective when it comes into contact with the green, growing parts of plants, also it will not move thru the soil to enter other non-target plants by the root system. (it won’t leech)

    In either case, at least in Florida one needs a limited spray license to spray ANY Herbicide

    So I'd have to agree with other possible casuses .... much like Scraper suggested
  8. John DiMartino

    John DiMartino LawnSite Silver Member
    Messages: 2,555

    I use roundup a lot,I dont think it would do that,I have never had it move thru soil,and like others said,its supposed to break down ,and totally biodegrades after a short time.
  9. plymouthvaliant73

    plymouthvaliant73 LawnSite Member
    Messages: 167

    I may have been too hasty in my reply, Brian did say grass and weed killer not total vegetation killer and they are different products.

    That said, I have used RoundUp very carefully on customer's properties primarily for driveways and curbs but somewhat aggressively on my own property around shrubs and sometimes had some damage. There can be less than visible mist and vapor even when you think you are being careful. RoundUp can be absorbed through thin young green bark or breaks in the bark but probably not through older coarse bark.

    The grass and weedkillers should not have affected the shrubs through the soil.
  10. Ron Persaud

    Ron Persaud LawnSite Member
    from Florida
    Messages: 17

    Roundup will not be taken up thru the soil; it has to contact a green part of the plant. Early symptoms of its action is a yellowing out in the leaf starting at the leaf base and moving out. I usually carry clippers to snip off any part of the desirable plant that gets sprayed. I also use tracker to show me where I have sprayed.
    Diquat is a dessicant which dries out the moisture of that part where it touches. Damage from Diquat will not spread or translocate from one part to the other.
    The unknown product is the Spectracide compound. Spectracide is a brand name for many turf care products and if the one that was used for weed control in the ornamental bed had 2.4D, then damage to these plants can be expected. 2.4D causes distorted growth and many buds to form where there should be only one. So look closely at the label. If you can rule out the weedkiller then it will free you up to look for other causes like insects and fungi.

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