Learn Your Lawn: Annual Bluegrass

What Is Annual Bluegrass?

Annual Bluegrass, or Poa Annua, is one of the most common varieties of undesirable weed grass that homeowners encounter on their lawns. In fact, almost every lawn will have some Annual Bluegrass. It can be a big problem, because it’s not only an eyesore, but it can also weaken a healthy lawn by using up its valuable nutrients.

Annual Bluegrass is a winter annual that thrives in cool weather when lawns can be susceptible to weeds and disease, most prominently in the late spring and early summer. Even though Annual Bluegrass and Kentucky Bluegrass are from the same family of grasses, Annual Bluegrass is much less desirable, as it cannot withstand heat or drought conditions and tends to die off in summer, leaving behind unsightly yellow patches in the lawn. 

How Can I Control The Amount Of Annual Bluegrass In My Lawn?

Almost every lawn will have some Annual Bluegrass, but what you do culturally will determine how big the problem becomes. If you’re at that point where Annual Bluegrass is taking over your lawn, start bagging your grass clippings while the seed heads are prevalent. This will help prevent the seeds from sitting in the soil, where they will germinate. However, this will only have a small impact on reducing the Annual Bluegrass in your lawn. It’s more important to improve your cultural practices and seed the lawn regularly using a suitable variety of seed.

A thick, healthy, well-maintained lawn is always the best line of defense. This can be achieved through beneficial cultural practices, which include:

• Watering: Deep and infrequent watering is essential for strong plant health and development. A general rule of thumb is to water each area of your lawn for 30-45 minutes, twice per week, in the early morning so the turf is dry by nightfall. 

• Mowing: Maintain a regular mowing schedule throughout the growing season. In general, you should keep your lawn between 2 ½ and 3 ½ inches high, but during the hottest weeks of summer, you may allow the grass to grow as high as 4 inches. Never remove more than ⅓ of the grass blade at each mowing.

• Fertilizing: Regular applications of Weed Man’s specially formulated, slow-release granular fertilizer will help provide your lawn with adequate nutrients. These applications are timed specifically to avoid over fertilizing the lawn.

• Core Aeration and Overseeding: Aerate and overseed annually to fill in bare areas with suitable seed and topsoil and to choke out unwanted grasses and weeds. This will help thicken the turf, so weeds can’t break through, and will improve soil drainage and alleviate soil compaction, allowing water and nutrients to penetrate deeper into the soil.

Your local Weed Man professional will be able to offer other solutions and recommend the best form of treatment that is suitable to improve the conditions of your lawn.