How can you control Poa Annua (Annual Bluegrass) in my Landscape Maintenance? The most important treatment is the application of pre-emergence before we hit nighttime temperature at 70 degree or lower for three nights in a row. After that, Poa Annua will began to germinate.
This will usually occur in Atlanta about mid September, maybe a little soon in Northern suburbs. Even though the Poa Annua has germinated, you can not see it. In November/December, application of Simazine will help control any Poa Annua that has already germinated.
Simazine will kill any recently germinating Poa Annua, and it will add an additional level of pre-emergence. One problem is that Poa Annua can sometimes build a resistance to Simazine. A warm fall will accelerate the growth of Poa Annua.
If it is too mature, the Simazine will be ineffective against it. On mature poa annua you will need to spray a post-emergent herbicide. You can spray Transit-X early in the season as it is unaffected by cold temperaatures. As early spring arrives, and temperature rise above 70’s, there are several post-emergent chemicals that can handle Poa Annua.
The best one in my opinion is Revolver. You need to be careful with all of these chemicals as they will harm fescue, liriope, and rye grass. The key is to identify Poa Annua early and to treat immediately.