Our applicators have been noting unusual amounts of Annual Bluegrass (Poa Annua) in many of our client’s lawns. This native grass is easily identified this time of year, due to the prodigious amount of small, whitish seeds it is now producing.
 
Poa Annua will produce seed at any mown height, and out competes all other grass species. By the end of June, Poa Annua will generally stop producing seed, making it much less noticeable.
 
These seeds germinate in the fall when the soil temperatures drop below 70 degrees and can remain viable for several years, germinating when conditions are favorable.
 
Generally speaking, it is not economically feasible to control Poa Annua, as it is much better suited to our climate than the more desirable rye grass / fescue blends most people prefer. However, if Poa Annua is in small patches, you can treat it with Glyphosate (Round-up) and reseed, or sod the spots.
 
There are some ways to discourage Poa Annua:
 
  • Water 2 days a week, 45 to 50 minutes per section. Less frequent, deep watering, favors deeper-rooted rye grass and fescue.
  • Mow at 3 inches or higher.
  • Aerate spring and fall, Poa Annua prefers compacted soil.
  • Promote good drainage. Gypsum, applied with aeration, aids in drainage.
Because Poa Annua is so wide spread and persistent, managing it and blending it into your lawn may be your best option. It is usually only obvious 6-8 weeks a year, when in seed. The rest of the time, other than a slightly “patchy” effect, Poa Annua blends well (compared to other invasive grasses) in most turf situations.