Every summer about this time I begin receiving phone calls from people wanting to know how to get rid of field sandburs, or commonly called grassburs. Field sandburs are a summer annual grassy weed that can be found in home lawns, sports fields, parks and along roadsides. This grassy weed is specially adapted to dry, sandy soils but can be found growing in other types of soil as well. The big problem with sandburs are the sharp, spiny burs that are part of the inflorescence. These burs can be painful and are difficult to remove from clothing material.
Field sandburs generally start germinating in late spring and will continue to germinate until late summer or early fall months. Ideally this is not the best time to treat for field sandburs, but this is when everyone thinks about it. This weed will continue to grow until the first hard frost or freeze occurs. However, if we have a mild winter the plant will survive and act like a perennial. This happens more so in town in well populated areas.
Field sandburs, the correct name for grassburs, are generally not a problem in well maintained turf area. With proper fertilization, mowing and irrigation, you can produce a turf that is dense enough to prevent sandburs from becoming a problem. Remember most weeds are “opportunist” that invades weakened lawns, the fight against weeds starts with good management. However if sandburs have become a problem, there are several effective herbicides available to control them.
In children’s play areas or other areas where soil is heavily traveled and compacted and grass is struggling, try aerating the soil to promote a healthier stand of turfgrass.
A pre-emergent herbicide such as Surflan, Dimension, Amaze, or Pre M can be effective in controlling sandburs and should be put down before the weed seed germinates. The date to apply pre-emergent in Somervell County in the Spring is usually March 1-15. Two applications that are 6 weeks apart should keep sandburs and other summer weeds in check. A pre-emergent application needs to be watered in thoroughly. Always read and follow label directions.
For post emergent field sandbur control, use MSMA or DSMA. These products will do a good job of controlling the field sandbur when it is young. As the sandbur matures, it becomes more difficult to obtain effective control. Remember, MSMA cannot be used on St. Augustine lawns. For these turfgrasses, you will have to rely on the use of a pre-emergent herbicide.
Other options include individual plant treatment, spot spraying, with Round Up if you do not mind brown, dead spots in the yard. You can also individually hand weed each plant. And if you are mowing try to catch the clippings where field sandburs are present to try to avoid spreading more seed.