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Killing Clover in Dymondia

Discussion in 'Pesticide & Herbicide Application' started by BigTree, May 19, 2010.

  1. BigTree

    BigTree LawnSite Member
    Posts: 17

    The client has Dymondia Margaretae planted between walkway stepping stones. It has made a very durable and attractive mat without getting overgrown like grass. There is a 'weed' (see attached photo) that is starting to take over the Dymondia (see attached photo). It starts in a small area and ends up making a complete mat. Manual removal is proving to be very labor intensive as it has not been possible to effectively remove the root system so it continues to gain ground. I plan to try a herbicide and apply it with a Q-Tip ONLY to the weed leaf(as I know that the Dymondia will die if I use the herbicides that I have on hand - see below - and spray it on). This will be done each week until the weed is under control (it may seem that this is labor intensive but it is far easier to do than manual weed removal). CAN YOU ID THE WEED? CAN YOU RECOMMEND A HERBICIDE THAT I CAN APPLY TO A TRIAL AREA ONLY ON LEAVES VIA Q-TIP TO SEE IF IT WILL WORK? THANKS.
    Herbicides that I have on hand include (I can buy others if necessary):
    Ortho Weed B Gon Max plus Grabgrass control
    Bayer Advanced All-In-One Lawn Weed & Grabgrass Killer
    Ortho Weed B Gone Max plus Crabgrass Control.


  2. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 12,215

    That is oxalis, (yellow wood sorrell). Difficult to kill. But its edible--tastes like sour apples, only better.
    Spraying it is probably not going to work. Maybe you don't have any cold weather in winter where you are--but if it comes up from seed every spring instead of remaining over the winter--then a pre-emergent that blocks the seed might be the best bet. Look for a preemergent that lists oxalis on the label.
    Let us know what happens Bigtree, OK?
    And don't bother painting weed killer on the leaves--the stem (mainly the top inch) is the only important part that is affected.
    A herbicide like Quicksilver is highly effective on very young weeds. If you can find a time of year when the oxalis is very young and the good stuff is mature or dormant--it might work. Might.
  3. BigTree

    BigTree LawnSite Member
    Posts: 17

    Thanks RigglePC for your very helpful insights/data. Are you saying that the herbicide that I would be using is only taken in by the stem? - not the leaves? I do live in a temperate climate and the Oxalis seems to stay alive all year. But a pre-emergent herbicide may keep down new seed growth - of which there is surely some every year. Thanks again.
  4. sunstone

    sunstone LawnSite Member
    Posts: 1

    Hello Big Tree
    We have the same oxalis problem in dymondia. What pre-emergent have you used and have you noted any adverse effects on the dymondia?
  5. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 12,215

    Hand pulling is probably your only option, Bigtree. If it sticks up high--sure hit it with a sponge on a stick. Or try my poison ivy tool, (two small sponges tied to a long handled pair of barbeque tongs--wet the sponges with weed killer--grab the weed and pull the sponges along the stem. )

    I could be wrong, but I believe that most weed killers affect only the rapidly growing parts of the plant--the top inch or two. The rest does not matter--although you will get some curling of the leaf stems (petioles).
  6. dgw

    dgw LawnSite Bronze Member
    from OH
    Posts: 1,008


    as i think we talked about in another thread i have been doing my apps due to a unforeseen event with my fert guy

    i can actually hear the oxalis laughing at me as i spray it with 992

    any tips?

    and my browning grass recovered to about 80% so far, thanks for the info
  7. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 12,215

    I prefer something with triclopyr--like Ortho Clover, Chickweed Oxalis killer (8 percent triclopyr). oxalis is waxy--sheds water--be sure to include a surfactant or detergent.
    Last edited: Jun 13, 2010
  8. BigTree

    BigTree LawnSite Member
    Posts: 17

    Herein is my battle (me vs oxalis) story for the past 12 months.

    Problem - Rid the Dymondia of Oxalis without killing or replanting the Dymondia. In addition to Oxalis, there were two other weeds in abundance (but not nearly as abundant as Oxalis) in my Dymondia: spotted spurge which is common in California; and another weed that I have not yet identified(it is vinelike and sends up tiny thin shoots straight up about 2-3 inches above the Dymondia).

    Severity - The Oxalis was rapidly taking over the Dymondia as of June 2010. In some areas there were spots as large as 5 inches in diameter where the oxalis had squeezed out the dymondia almost entirely.

    Hand Weeding - Hand weeding was very time consuming and entirely unsuccessful with both the oxalis and the spurge as it came back much faster than the Dymondia could infill - and it even seemed to come back better! The oxalis root system is very extensive under the Dymondia in a lateral direction and the roots will break (in the soil I was dealing with which has some clay in it) prior to being able to pull out any significant amounts of oxalis. Maybe if the soil was a silty loam hand pulling would be an effective means of control - but certainly not in the soil that I was dealing with.

    Triclopyr - Got some ortho weed be gone for chickweed, clover, and oxalis. I found that the best way to apply this (after trying brushes, q-tips, sponges between calipers) was by first putting on thin latex exam gloves (to minimize skin absorption) then putting thin cotton gloves, then dipping fingertips into the triclopyr and touching the oxalis. The oxalis grows very close to the Dymondia so it was hard to get the oxalis covered without getting some on the Dymondia. I erred on using very little triclopyr as I did not want to kill the Dymondia. I did this a few times during the summer of 2010 but the it was not very successful. It seemed to stress the oxalis but I likely did not apply enough to successfully kill it. In one spot I spilled a thimble of triclopyr and after a few weeks the Dymondia was very stressed and close to dead in that area. Prior posts stated that oxalis was very waxy and that a surfactant would be needed. I tried it both with/without surfactant and found it was nearly impossible to coat the oxalis without it and difficult to coat even with it. I am not saying that the triclopyr would not kill the oxalis, rather, I am saying that the methods I used were not effective and that getting the proper methods (application, strength, etc) that MAY have worked would have involved more trial and error than my resources would permit.

    Pre-Emergence Herbicide - After doing some research I found only one that was listed for use on Dymondia for control of oxalis - Pendimethalin. Other pre-emergence herbicides that I looked at may have been safe but they were not listed as such. The product purchased (at Horizon which is big in western states) was Pendulum 2G - a granular product that comes in 40 pound bags (for about $100) - which covers a huge area (I imagine that you can also get it at John Deere Landscapes and Ewing if they are near you). I applied a dose in early january 2011 and another dose about 8 weeks later - not sure that my application timing was perfect - but that is what I did.

    Winter 2011 Weather - I live about 25 miles inland from San Francisco where we have much hotter summers (over 90 on most summer days) and colder winters (we get a few surface frosts each winter that 'freeze' leaves but does not penetrate the soil). This winter we had some cold nights (mid 20s) and a couple of especially heavy surface frosts.

    June 2011 Status - Presently there is practically no oxalis and no spurge in the Dymondia. This is a HUGE change since fall of 2010 when the oxalis clearly was poised for winning the battle come summer 2011. I am GUESSING that the winter frost 'killed' off the existing oxalis as it was thriving in January and gone in the spring. Further, the Dymondia not only filled in all the bare patches formally occupied by the oxalis but is also more robust and thicker than ever. The vinelike weed has been hand pulled this spring and has not re-emerged.

    Conclusion - I am GUESSING that the success in ridding the Dymondia of oxalis is some combination of ; 1) winter frost; 2) vigorous infill/growth of the Dymondia; and 3) use of the Pendulum 2G - with how much, if any, of the success being attributal to each factor unknown. This is about the 3rd winter for this Dymondia and other winters did not seem to kill off the oxalis (or if was killed it came right back in same locations from seed so it never seemed to be gone). Some of the above is conjecture - but clearly the oxalis was killed and prevented from re-emergence - so you may want to consider the above if you have a similar issue to deal with.

    Hope this helps!
  9. Ric

    Ric LawnSite Fanatic
    Posts: 11,956

    Dymondia Margaretae

    Are you sure that is Dymondia Margaretae???? It sure doesn't look like it from the pictures. Dymondia Margaretae has more of a longer pointed leave. What you show in the Picture looks more like Perennial Peanuts which the Herbicide PLATEU can be sprayed over the top.
  10. BigTree

    BigTree LawnSite Member
    Posts: 17

    It is Dymondia (the photos contain mostly oxalis - which looks a little like Perennial Peanuts in my photos) as it came labeled from a reputable nursery and looks exactly like Dymondia (in real life - but does not show well in my pictures).

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