UF LandGrant Wordmark

UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail: indianco@ufl.edu

 October 15, 2003

Feature Article - release the week of October 19, 2003

Dan Culbert - Extension Horticulture Agent

Sticky Sandspur

Another sign of fall is the number of questions sent our way about a very painful weed. Sandspur or sandbur is a grass plant that produces a sticker that can really get under your skin, and at this time of year the plant is producing its "fruit" that will carry it through the cooler seasons.

Today’s column will examine the how and where of this pesky weed’s growth, and give some ideas on how to prevent it from sticking around your Florida Yard. Our information comes from University of Florida Extension Specialists.

At least eight species of Sandspur are found in Florida, but two of these are most likely to be encountered in landscape situations. Southern Sandbur (Cenchrus echinatus) is a wide ranging grass that can be found from North Carolina to California, and is found through the Americas and Australia. Another likely visitor to your socks could be the Coast or Field Sandspur (C. spinifex) which may be found from Virginia and westward, again with worldwide distribution.

Left: Southern Sandspur (C. echinatus). photo courtesy of Auburn University.    Right: Coastal or Field Sandspur (C. spinifex).  photo courtesy of USF Atlas of Florida Vascular Plants

For the budding botanists out there, the difference between these two plants is in the seed: the Southern sandspur fruit has a ring of bristles as well as the coarser larger spines; the Coastal sandspur is covered only with the spines. Each fruit may contain one to three small seeds, which hitchhike on clothes, fur, or even tires to new locations.

 

Seed of Sandspur:    Left: Southern Sandspur (C. echinatus).                            Right: Coastal or Field Sandspur (C. spinifex).

Sandspurs are summer annuals, which means that it takes one growing season for a seed to germinate, grow, flower and produce the seed for the next generation. And then they drop seed right in the same spot too, so it seems like they grow year after year in the same spot. They have a preference for dry sandy sites that have lots of sun. Does that sound like your yard?

Seed start growth in the spring, and by the end of summer, they have produced several seedheads each with many sandspurs. There are few complaints about sandspur in the spring, when the plants blend into turf areas or roadside without notice. Once they produce their fruit, the sticking begins, and that’s why we hear about it in the fall.

A general principle of weed management is to encourage vigorous growth of the desired turfgrass so that it can out-compete with undesirable plants like the sandspur. This is done by making sure that the site is adapted to growing grass in the first place, and taking care to apply the three rules of Florida-friendly turf care: mow, irrigate and fertilize correctly.

That translates to a 4" cut, no more than 1/2" of water between wilting, and one pound of actual nitrogen per thousand square feet. Scientists tell us that sandspur seeds actually grow better if nitrogen fertilizer is low. Call me if you need more details on these principles of turf management.

 

Once you follow these rules, if your yard needs the help of herbicides, consider this: it is easier to take care of young seedlings than it is to kill mature plants with seed. There are no weed killers that will make the sandspurs disappear in the fall.

The better approach is to use what are called "pre-emergent" herbicides in the spring - and this means mid February in our area. Be careful to use a herbicide that is labeled for use on your kind of turfgrass. Unfortunately, there are fewer preemergent herbicide products available for use on Bahiagrass than there are for St. Augustine grass. If you are not sure what kind of grass you have, bring us a sample.

So if your grass is a sticky mess, get your lawn in shape now, and make a note on your calendar to apply a labeled herbicide product in the spring. Then next fall, you’ll be enjoying your Florida Yard rather that pulling spines from your socks and Fido’s fur.

Our office has a fact sheets on managing sandspurs with weed killers, and we can offer more ideas on the safe use of herbicides that can help manage these weeds. If you need additional information on sandspurs, call or stop by our office at 458 Hwy 98 North. Our phone number is 863-763-6469, and you can visit our website at http://okeechobee.ifas.ufl.edu or email me at indianco@ufl.edu

References

SandspurHall, David W., Vandiver, Vernon V. and Ferrell J. A.. Coast Sandspur (Field Sandbur), Cenchrus incertus.  Gainesville:  UF/IFAS Florida Cooperative Extension Service, SP-37. January, 2012. 

Hall, David W., Vandiver, Vernon V. and Ferrell J. A.   Southern Sandspur ,Cenchrus echinatus.  Gainesville:  UF/IFAS Florida Cooperative Extension Service,  SP-37. January, 2012. 

Unruh, J. Bryan,  Brecke, Barry  and Trenholm, Laurie E.  Weed Management in Home Lawns Gainesville:  UF/IFAS Florida Cooperative Extension Service, ENH-884.  April, 2010

Wichman, Tom.  Sandburs  in:  Gardening in a Minute (website).  Gainesville:  UF/IFAS Environmental Horticulture Dept., June 2008.  http://gardeningsolutions.ifas.ufl.edu/giam/problems/weeds/sandburs.html

Wunderlin, R. P., and B. F. Hansen. 2008. Atlas of Florida Vascular Plants (http://www.plantatlas.usf.edu/).[S. M. Landry and K. N. Campbell (application development), Florida Center for Community Design and Research.] Institute for Systematic Botany, University of South Florida, Tampa.

 

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