Q: Is there a weed killer that I can spray onto centipedegrass to kill sand spurs?
A: Few things take the pleasure out of walking barefoot across a lawn like stepping on a sandbur. The plant is an annual grass that grows from seed each spring. The spur is the hard, spiny part of its flower. Fortunately, since it sprouts from a seed, the best way to control it is to prevent seed germination. You’ll need to read the ingredient label of several lawn pre-emergent products (click for sources) and find one that contains either oryzalin, pendimethalin or bensulide.
Apply the pre-emergent chemical in the first week of March each year, making sure to water it into the soil. Repeat twice more, at six week intervals. Follow the same schedule the following year. Sandspur, along with many other annual weeds, will be stopped in its tracks. Burs that lie in wait in your yard right now will decompose in a few months.