Photo courtesy of the Richmond County Cooperative Extension
Sandburs like this one greatly reduce hay and pasture quality, and palatability for grazing animals.
Last week, I got a call to look at a thinning bermudagrass hayfield that was not performing well. While explaining to the farmer that declining stands of bermudagrass usually means soil pH or nutrients are low, I noticed a patch of grass at our feet that often goes unnoticed this time of the year. After pulling a handful and getting a closer look, I broke the news that he also had a bit of a field sandbur (commonly called sandspur) infestation.
Although sandbur germinates in mid-spring, it usually flies under our radar until July when it begins developing those pesky burs that painfully stick to everything they touch. Sandbur’s ability to hitchhike on humans and animals allows it to easily spread (inside the burs are viable seeds). In the livestock world, this weed is more than just a nuisance. Infestations greatly reduce hay and pasture quality, and palatability for grazing animals.
When managing sandbur, the earlier you identify it in your field the greater your chance of controlling it. Once the burs or seed heads begin developing on the plant, most herbicides lose their effectiveness. Sandbur is classified as a grass with long, narrow leaves and a flat stem. Sandbur is a bunch grass which means it does not produce stolons or “runners” like bermudagrass or bahiagrass. Its bunching growth habit is a good way to identify this noxious weed before it begins producing seed heads or burs.
Once you identify the areas where sandbur is present, it’s time to start thinking about management options. Sandbur thrives in soils with low fertility and can tolerate low pH. Taking a soil sample and applying the recommended amount of lime and nutrients is the best thing you can do for any type of long-term weed control. Getting those essential nutrients out on your pasture and hay fields will give bermudagrass and bahiagrass a competitive edge by filling in those thinning areas and suppressing troublesome weeds like sandbur. In pasture situations, leaving a 3 inch stubble height when grazing will also help bermudagrass shade out weeds.
After you get your desired forage fertilized and healthy, if there are still some weed issues it’s time to look at herbicide options. Although there are several products for sandbur control in turf and lawns, there are only a few labeled for hay and pasture. Products that are labeled for sandbur control are Pastora, Pendimethalin, and Panoramic. Research from Oklahoma State has shown that Pastora effectively controlled sandbur prior to seed head development while Panoramic was effective on smaller/younger sandbur plants.
An important note: Pastora and Panoramic may cause slight stunting to bermudagrass and should not be applied to bahiagrass. Our other option, pendimethalin, provides fair control of sandbur but must be applied in the early spring before sandbur seeds germinate. Pendimethalin is a preemergence herbicide which means it inhibits seed germination only. If you have sandbur coming up in a few patches you can spot spray areas with glyphosate. Remember that glyphosate is a non-selective and will injure any bermudagrass in the application area. Whatever product you choose, remember to read the label and follow all guidelines.
With few herbicide products available to control sandbur in hay and pasture, your primary tools against infestations are cultural methods such as good grazing practices, correcting soil pH, and applying the right amount of fertilizer. An integrated approach using these cultural practices coupled with appropriate herbicide applications is the best management practice.
If you have any questions about weed management in hay or pastures please contact the Richmond County Extension office at (910) 997-8255.
Anthony Growe is the Livestock and Crop Agent for the Richmond County Cooperative Extension.