Annual bluegrass is a clump-forming annual grassy weed that comes back from seed every year. It tolerates very close mowing, so leaves can range from 1/2 inch to 11 inches tall, depending on where it grows. Growth is erect and arching.

Annual bluegrass leaves are light green in color, especially when compared to its close relative, Kentucky bluegrass (Poa pratensis). Annual bluegrass leaves have a boat-shaped tip. Before they open fully, the smooth leaves are folded within the stem, not rolled. Annual bluegrass flowers are an open, branched, pyramidal panicle of seed heads.

In contrast to Kentucky bluegrass, which spreads via underground stems known as rhizomes, annual bluegrass has fibrous roots and no rhizomes.


Annual bluegrass is primarily a lawn and turf weed. You'll find it throughout the United States, in both northern and southern lawns. It's also common wherever the soil has been disturbed, including new construction sites and agricultural fields.

Annual bluegrass tolerates a wide variety of soil types, but has limited tolerance for drought. During winter months, this grassy weed shows up easily in dormant warm-season southern lawns. It can spread swiftly by seed, germinating year-round when the conditions are right. Once established, annual bluegrass grows and flowers rapidly.


When treating annual bluegrass or any lawn weed, always read product labels carefully to ensure the product can be used on your lawn type. Some lawn grasses are sensitive to certain herbicides, so check labels before applying. Only treat established lawns. For best results, treat annual bluegrass when newly emerged weeds are young and small.

Image Herbicide offers several highly effective liquid products to kill or control annual bluegrass:

  • Image Kills Nutsedge Ready-to-Spray is a selective, post-emergent weed killer for use in southern lawn grasses. It works to kill and control annual bluegrass and other listed tough, hard-to-kill weeds. Just attach the container to a standard garden hose; the product automatically measures and mixes as you spray.
  • Image Kills Nutsedge Concentrate, designed for use with a pump-style sprayer, selectively kills emerged annual bluegrass and other listed summer and winter weeds in southern lawns. Use this product to spot treat weeds or treat large lawn areas.
  • Image Casoron Granules prevent annual bluegrass from emerging around established woody plants, including roses and listed shrubs, trees, fruits, nuts and berries. Just sprinkle the granules on the soil surrounding label-listed plants, and water-in according to label instructions. For best results, apply in early spring or late fall, when temperatures are cool. This product prevents annual bluegrass regrowth for up to one year.

Annual Bluegrass Control Tip: Annual bluegrass can set seeds even when cut very short. Treat this weed before it sets seeds to break the cycle for next season. Crabgrass-preventing spring lawn treatments such as Pennington UltraGreen Crabgrass Preventer Plus FertilizerIII 30-0-4 also help prevent annual bluegrass seed from establishing.

Always read product labels thoroughly and follow instructions, including guidelines for lawn grasses, pre-harvest intervals (PHI) and application frequency.