The Ongoing Battle with Burclover: Organic vs. Chemical Control

The Ongoing Battle with Burclover: Organic vs. Chemical Control

Burclover is a commonly used name for two prickly invasive clovers, Black Medic Medicago lupulina  and California Burclover Medicago polymorpha.  Since the beginning of the last drought we had, probably around 2007, my neighborhood has slowly been overtaken by burclover.  It is the tiny clover looking plant with yellow flowers and then prickly spiral shaped seed pods that stick to beach towels, picnic blankets, and dog fur.  I have been hand pulling it from the beginning, not wanting to resort to chemicals for control.  Each week, prior to mowing, I spend a  few minutes or so, going over the front lawn looking for any new signs of it to pull.  This time of year, it is slightly darker than my Bermuda grass so it is easy to spot.  At the neighbor’s house, I spot it even easier with all the tiny yellow flowers on larger established patches.

kill weed in lawn that has stickers
The pretty yellow flowers of the burclover make it easy to spot this time of year

My previous efforts to eliminate it have been futile, so much so it makes me want to cry.  I feel bad for our Golden Retriever because he gets the burrs stuck in his fur. We either have to hand remove them or we use a slicker brush to get them out. The whole neighborhood has these burrs, with a few lawns on the block that look like all they have now is burclover.  It seems to be easily spread by the pets, the yardmen, and the kids.  With the water restrictions, thin bare patches began to make the lawns on the block ideal for the burclover to take over.  After discussing it with the next-door neighbors last month, we have decided to team up to each make a concerted effort to get rid of it over the next few seasons.  I compiled a page of control methods suggested by U.C. Davis ANR and Cooperative Extension and shared with the neighbors.  Neither of the households are organic gardeners like me and they would prefer to use the easiest or fastest method available. They are from the generation that was brought up to believe in “better living through chemicals.”

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Wednesday, I spread a few bags of an organic product, Safer Weed Prevention, made with corn gluten meal, all over the front lawn and parkway.  Although I spread compost on the lawn at least once a year, Safer Weed Prevention, and similar brands like it, is a natural fertilizer that is also reported to have allelopathic properties to inhibit the growth of broadleaf weeds, like clover.  It wasn’t necessary to spread it out back since the burclover has never managed to get a foot hold. The chickens and tortoise like clovers and enjoy munching on any patches that manage to germinate.

U.C. Davis ANR and Cooperative Extension suggest some “best practices for control,” for both organic gardeners like me that want to avoid synthetic chemicals and folks like my neighbors that just want to kill it by the easiest means possible, as long as it doesn’t pose a risk to the kids or pets, and be done with it for half a year. With all pesticides and herbicides, even the organic ones, carefully read and follow all the directions on the label. The following is adapted from information at UC ANR that I shared with the neighbors:
what are the burrs that get stuck in pet fur
A small area of lawn at one of my neighbor’s houses. The burclover makes up a large portion of the turf.

MANAGEMENT OF BURCLOVER

Clovers are relatively easy to control in the home garden by hand-pulling, cultivation, and the application of mulch. In large, landscaped areas herbicides may also be necessary. Clover has a hard seed coat and is heat tolerant. Solarization and composting will typically not eliminate or kill it. Because of the hard seed coat clover lasts a long time in the soil and can germinate many years later. Controlling burclover and other clovers will require an ongoing effort.

Once clovers are controlled, change cultural practices in the landscape and turfgrass to reduce the chance of reinfestation. Keeping the lawn thick and healthy helps to exclude clovers from reestablishing. Lack of nitrogen fertilization can also influence clover growth.  Maintain a seasonal fertilization regimine.  Mulches can be effective in excluding clovers and other weeds in landscapes.

ORGANIC CONTROLS – Natural Ingredients and Organic Based Methods

Annual clovers can be easily controlled by hand-pulling, hoeing, or cultivation. Mulching, depending on the size and depth of the mulch, can prevent seedling establishment. Before weed seeds germinate, apply a 4-inch thick organic mulch to prevent the establishment of clovers. Organic mulch can also be applied after the seedlings have germinated but must be applied in a thicker layer (4 to 6 inches) and must cover the plants completely to block out all light. Organic mulches need to be reapplied each year to maintain the 4-inch-thick layer because they decompose and the thickness of the mulch declines over time. High-quality thick Woven black landscape fabric can exclude weeds over a number of years. Larger plants are more difficult to control with mulching, but they can be hand-pulled or hoed.

CHEMICAL CONTROLPost-emergent Herbicides

Both established annual and perennial clovers can be controlled with postemergence herbicides. The best herbicide to use depends upon the species of turfgrass. Warm-season turfgrasses such as bermudagrass, zoysiagrass, and kikuyugrass will tolerate products containing mecoprop and dicamba but not triclopyr. Cool-season turfgrasses will tolerate all of the herbicides that control clover. The herbicide 2,4-D is not effective for clover control; it will injure the plant but does not eliminate it. TREMEC is a trade name for a chemical herbicide that contains mecoprop, dicamba, and 2, 4-D, to control bur clover and other lawn weeds.

In North Orange County, my parents have also been battling burclover in their Marathon lawn in the backyard during the drought. My father hates Bermuda grass and decided to use the Turflon Ester product on it to get rid of Bermuda but keep the Marathon lawn. The herbicide has many of the above mentioned herbicides in its formulation. The Turflon Ester not only eliminated the few patches of Bermuda grass from his Marathon lawn over a couple of seasons applicatons, and along with improved irrigation and fertilization. He was happy to report the ever-expanding patch of burclover disappeared along with the Bermuda grass lawn weeds.

CHEMICAL CONTROL- Preemergent Herbicides

Preemergent herbicides available for landscape use are effective but generally unnecessary in the home landscape where annual clovers are easily controlled by the methods mentioned. For landscape professionals, herbicide formulations that contain isoxaben, sold under the brand name “Gallery” are effective for controlling annual clovers and can be used around many woody shrubs and trees. Most established annual flowers tolerate this herbicide. Herbicide formulations containing oryzalin, trifluralin, or pendimethalin will control most grass species and some broadleaf weeds but will miss many other broadleaf species, including legumes like burclover.

CONCLUSION

As I mentioned at the beginning of the post, I am an organic gardener, and prefer to use the more enviromentally safe methods to deal with pests, weeds, and disease that are available. I have had sucess dealing with burclover and other weeds this way, however, I understand that not everyone feels the same way I do or doesn’t have the time and patience. If burclover is taking over, don’t feel bad if you have to resort to a chemical herbicide. If you do use any product on your yard (Organic or chemical), please make sure to carefully read and follow all the directions on the label and use caution around pets and children.

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15 thoughts on “The Ongoing Battle with Burclover: Organic vs. Chemical Control

  1. I almost forgot, weed barriers don’t work here! I skipped the process when I laid down six yards of 1-1/4″ Grey Granite River Rock for My zero scape and ‘pesty animal barrier’ around My home(got a bobcat living underneath right now). It seems as all that is needed to germinate a seed here is a few ‘grains’ of soil(dust), a little wind(like the Santa Anna’s, a drop of H20 or 40% RH and 85*F ambient and your off and germinating! Say, as far as Photosynthesis, the next cycle, isn’t anyone concerned about wanting to “KILL” all the CO2(Carbon Dioxide) on the planet that is necessary for all Plants to absorb, scrub and exchange into O2, ya know, that stuff we breath that keeps us alive? Lol………………

  2. I’m happy to hear you say not all methods work for everyone. In Central Western Nevada the soil is on the Alkaline side with a sandy base, just ripe for these boogers! My back half Acre is full of them and neighbors upwind have given up. These are One and Two Acre Parcels, so when I hear pull them with a specific tool, My thought is, “how long do you think you would last on My Property! Ha, Lol.
    Our Location is also “High Wind Prone” to be modest! 80 MPH winds happen so the germination is coming in from California! Ha, serious, there has got to be a better way. I have killed two of My Trees…..1 Maple and 1 Ponderosa Pine I planted 11 years ago. A nasty milky ground clear is all that controls them but look out! Get some extra rain and I’m positive soil peculation zapped them! Grinding them down with my second Mower Tractor is like pee’n on a Forest Fire! Could I Zapp the soil with a opposing PH Chemical that would spit out those Burr Clovers, Sow Thistle and Sandburs? This is ridiculous!
    Last request, do you travel, make house calls, work for ..50c an hour? I would love to see this “just pop ’em right out” concept! Haaa Ha LOL!

  3. i live in south Louisiana, and everyone in town has this burrclover! I can’t take my little sish-Tsu for a walk, as he gets full of the burrs. Do they ever go away? or am i going to have to put up with them until winter? The flowers are not yellow on the clover, but white, and the burrs are flat. I am so tired of picking them out of my dog. even when we go to the park, they are in the st. augustine grass. I thought about seeding with bermuda, but on your blog, i see they grow in burmuda also. My yard is much too big to pull out by hand, and i really don’t want to use chemicals, as i am afraid they will hurt my precious dog.

  4. Thank you so much for the info!!! Exactly what I have been searching for; along with what CA natives are good to save and spread! I was wondering though, where do you get ‘corn gluten’? I have never noticed it, & by a quick search, walmart doesn’t seem to have it!
    Thanks!

    1. I had trouble finding it when I first tried using it more than a decade ago, but for at least five or six years I have seen it at most independent nurseries. Other places like home de pot or amazon carry it too, but per pound, its more expensive. Look for a brand named “Concern”. Its not cheap, probably twice or three times the price of chemicals.

  5. I have a rule in my yard that I have to pull burrclover as soon as I spot the yellow flowers and put it in the trash can (NOT the compost heap!). In the spring I can pull it with my hands. My theory is not that it won’t come back from the root, but that I won’t let it go to seed. This has worked pretty well for me, but my boyfriend has a whole acre that doesn’t get watered in the summer (he’s on a well), and the burr clover has taken it over.

    There is also a slightly different weed that looks like clover but has small bluish white flowers and makes a different type of burr. I can’t find a name for it online and am wondering whether it could be a hybrid of the yellow burr clover with white clover. Or maybe it is subterranean clover.
    We thought it was regular white clover and were letting it grow, but when since the seeds came on they are a big nuisance. The burrs look like several small seeds in a cluster, each of the small seeds having a spine. Can anyone tell me anything about this plant and how to get rid of lots of it?

    Thanks.

    Martha

  6. Quick questions: What tool are you using to help pull up the roots of the clover? Just a regular spade?
    Do you dig about an inch or two from the base? Closer or further away?

    1. Kathleen,
      Actually, I use my hand most of the time. I try to do it a few days after whenever we get rain, or if I turn the sprinklers on, I do the next day so the soil is soft, just before mowing. After mowing the burclover is harder to spot. I make sure to find all the leaves/ stems on each individual plant and gather them all together in my fist and pull slowly trying to get the thin tap root. If it breaks off, or if the soil is bone dry, I use what I think is called a dandelion fork or dandelion weeder. It is inserteded about 4 inches down into the center of the plant and used to pry it out while trying not to disturb too much surrounding turf. I am sorry but I am not 100% sure that dandilions fork is the actual name. I got it 20 years ago from my mom. It looks like screwdriver with a forked tip and a wooden handle. It’s great for pulling dandelions. On a side note, the chickens and tortoise love it when I pull dandilions out of the front law for treats for them in the backyard.

  7. It has now been a few years since your neighborhood waged war on the clover. How is it going?
    I knew about burrs in the grass when I was growing up and discovered that we had it at this new house last year. It wasn’t until I was weeding in my front yard this year that I realized that the clover I thought was harmless was really the culprit. Now I am waging war!!! What was your most successful treatment plan?

    1. With the drought, the burclover still persists in the dying lawns’ bare areas. Lush lawns have few spots for seeds to germinate. One neighbor treated multiple times with herbicide, replaced broken sprinklers, and reseeded the lawn. She has some burclover, but much less than she used to. The neighbor on the other side treated with herbicide once, waters the lawn lightly but frequently, and the burclover is everywhere these days. The dog tracks a few seeds every year from that lawn to ours. I have kept it under control with hand pulling. I have about the same amount of burclover each spring as the neighbor that renovated and diligently applies herbicide annually now in late fall. I examine our lawn for new seedlings prior to mowing each week and hand pull any i find. Therefore, I think both herbicide and pulling are equally effective, but it is a constant fight or the burclover comes back, well unless all surround homes get rid of it. With the lack of rain this winter, I am guessing our lawn will be dead sooner than in past years.

      1. Thank you for the update. I am going to start the good fight tonight even though the plant has already gone to seed here. I may be seen vacuuming my lawn with our shop vac tonight because so many of the burrs have already broken off when I was pulling yesterday. I really want those suckers gone for my toddler’s sake and for the sake of our poor dog.

        1. Have you vacuumed the seed before? is it effective? I have so much in my unlandscaped “weed yard” that is driving me nuts!

  8. I have had issues but nothing to the extent that I saw in the photo. I do use a “weed and feed” fertilizer about once every two to three years to take care of the issue. I know organic is a way of thinking, but even “doctors” have to issue prescriptions every once in a while. If it is affecting your pets, I would certainly consider taking the treatment to the next level. Keep the posts coming, I really enjoy your blog.

  9. What an informative post. Years ago when the marathon lawn that we had was getting really weedy and we found out the only way to irradicate them was with strong stuff including arsenic, we plugged in St. Augustine. It is a tough lawn that does not tolerate many weeds and takes less water than other lawns. I am in So Cal too. Thanks for all the info. I do see a couple of those in my lawn but not often. I think all the gardeners everyone uses spreads these weeds now. No one mows their own lawn any longer keeping their weeds contained in their yard. We do so maybe that helps.

I would love to know what you think about this.

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