Poa annua is favored by frequent irrigation, compacted soils, short mowing, and overfertilization (especially early spring fert). These are cultural conditions that can be somewhat controlled. However it is so prolific in some areas, that some golf courses have even gone to trying to preserve the annual blue.<p>If you can educate the client to accept it in some areas, sometime you are better off. Have seen a pre-em application in late Aug in our area control it, but then you cannot reseed until next spring because of the pre-em. Care must be taken in choosing a short lived pre-em for this reason.<p>I have one large lawn that has a front yard of reg blue, part back yard of Poa trivialis (always wet, shady, heavy soil), and another back yard of Poa annua (compacted - can't aerate effectively because of tree roots, shady, never dries out). Have only lost the annual blue one year out of last 12, and next year it was all filled in with little effort on my part. The client accepts this practice, because removing 6 fabulous oaks is the only way we're going to get anything else growing there.<p>Detailed dissertation on Poa annua at: http://www.agry.purdue.edu/turf/pubs/ay41.htm<p>----------<br>Jim<br>North central Indiana<p><br>
I'm assuming it's in bermuda. Use a pre emergent in September and if that does'nt suppress it enough use Kerb as a post emergent spray. Kerb works best in cool weather and is a restricted pesticide, but it works good on poa annua.
Sorry, tazz, didn't check if you were north or south. Guess you southern guys have easier ways to control Poa annua. But down there it is really annual. We can keep it alive in northern areas, unless a heat fluke hits us.<p>Lawrence- also called roughstalk bluegrass, but most common "common name" is usually just your first, "Poa triv". Lot easier to say. <p>----------<br>Jim<br>North central Indiana<br>
We have both rough and annual bluegrass they are not the same. Poa annua is very low growning and fairly dark green. Poa trivialis is a perenial that is more yellow green and taller & faster growing. Poa trivialis is becoming a big problem in fescue for us.
The seed germinates in cool weather from late summer to late fall. To prevent seed germination use DCPA (DACTHAL) in early to mid fall depending on your area (the farther south - the later). Core aeration will help in fighting new arrivals of annual and cutting the grass above 2 1/2" will also help as lawns above this height rarely see Poa Annua.