May 27, 2015
Sandbur 2015
Few weeds are as disliked or as difficult to control as sandbur. There are more than 20 species of sandbur but only two are found in this area. Approximately 75% of the sandbur in this region is field sandbur (Cenchrus longines) with the remainder being southern sandbur (Cenchrus Encinitas). The burs are stiffer and longer than those of bur clover but not as stiff as those on puncture vine. Their ability to stick onto almost anything aids in their distribution. They are difficult to remove and often break off in your fingers and cause temporary numbing of the nerves. Field sandbur has a long thin leaf that resembles bermudagrass. The burs are yellow and there are relatively few of them compared to southern sandburs which are denser, have a reddish coloration and a broader leaf. Both have similar growth habits. They are supposed to be summer annuals but many plants will overwinter and come back the following season. They also both are found almost exclusively in sandy soil. No one has ever explained to me why this is. Postemergence grass herbicides don’t work on sandbur. It can be adequately controlled with preemergence herbicides (Prowl, Treflan etc.) but these won’t work on plants that have overwintered. Each bur contains 3 to 6 seeds that germinate in the bur.



To contact Marco Pena go to: marcop@ag.arizona.edu