Q: I am trying in vain trying to control annual bluegrass. I put down pre-emergent four times this fall. There is noticeably less than last year, but still plenty of it. Could we have a species that survives the summers here?
A: Golf course managers and commercial landscapers are bedeviled by annual bluegrass, Poa annua ssp. annua. Indeed, in the last couple of years they have recognized that some sub-species of annual bluegrass exhibit perennial behavior. They don’t die in May as expected. Scientists have given this type plant the name Poa annua ssp. reptans. Both sub-species produce thousands of seed but the perennial type is more prostrate while the annual type is more clump-forming. Even so, persistent applications of pre-emergent and good attention given to maintaining a healthy, vigorous lawn will usually bring annual bluegrass under control after a few years.