Further assistance with weed identification is available from any Clemson Extension office. Annual bluegrass reproduces by seed. Annual bluegrass prefers shady, moist sites and invades weak, thin lawn areas, especially low spots and flower beds where standing water occurs. It mainly germinates in late summer through early fall when nighttime air temperatures drop to the mid-70s. This usually occurs from September 15 to October 1 in the Coastal Plain and Sandhills areas, and September 1 to 15 in the Piedmont and Mountain areas.
Further germination occurs in early winter with warm days and cold nights.
Annual bluegrass has smooth, apple-green leaves with two clear lines, one on each side of the midrib that run down the length of the leaf blade. The edges of the leaf tip curve inward like the front of a boat. Handpulling is a simple, practical approach for small areas. Finally, improve surface drainage. Preemergence herbicides are available depending on the kind of turfgrass and ornamental plants grown.