Annual bluegrass has long been a problematic grassy weed in high maintenance turf areas such as golf course greens, tees and fairways.  In recent years, annual bluegrass has emerged as a lawncare problem as well.  Annual bluegrass, as its name implies, is an annual grassy weed.  It thrives in the spring and fall but suffers severely in the heat of the summer.  Prolific seed production allows annual bluegrass to invade new voids or reinfest bare areas which were previously annual bluegrass before the summer heat set in.  Currently, annual bluegrass is blooming and setting seed making it very easy to identify this light green grassy weed.  Control is more difficult than identification.  In some situations, managing annual bluegrass is actually more practical than attempting to control it.  More information can be found at the Purdue Education Store and search AY-41-W: ID and Control of Annual Bluegrass and Rough Bluegrass in Lawns