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>