Tom: Are you saying that Poa is going to take over the greens on all the courses? It was kind of disappointing to me when I saw it on a number of the greens at Sand Hills.
Jerry Poa is tough to keep out of golf courses when it's in the right environment and unfortunately it's a very adaptable weed. There are currently a couple of promising chemicals close to approval that can do a great job of killing it but they are still about a year or two away. Here is a little poa info for you that will help you see why it's so hard to keep off golf courses.
Some Interesting Facts about Poa annua
Depending on the climatic region Poa annua is a plant that you either try to manage as a desirable turf, or it is a weed to be removed. Its evasive characteristics are due in a large part from the evolution of different survival strategies (Cline et al., 1993). One strategy is its broad genetic base resulting in a wide range of genotypes within a small area like a golf green. Poa annua has also maintained its ability to flower and produce seed under low mowing heights.
Poa annua (annual bluegrass) uses 4 to 35% of its top growth (dry weight) for seed production. As a reference, annual plants like cereals invest 20 to 50% of their top growth for seed production.
• Annual seed production on a golf green is between 150,000 to 650,000 seeds per meter squared per year (177,000 to 767,000 seeds / square yard / year). The majority of this seed would be produced from spring through early summer.
• Approximately 75,000 to 225,000 tillers per meter squared per year flower (88,000 to 265,000 /square yard /year)
• During the growing season annual bluegrass tiller mortality is roughly 100,000 tillers per meter squared per month (118,000 tillers / square yard / month). Annual bluegrass has a strong potential for replacing dying tillers with new ones. Obviously sustaining favorable growth through the season is critical in maintaining annual bluegrass turf.
• Annual bluegrass seed dispersal is passive. The mechanism of dispersal is by human (animal) or equipment. Annual bluegrass has been found where human disturbance has occurred, which means it is found on all 7 continents.