Annual Bluegrass in the fairways

This year we have been using a plant growth regulator(PGR) for the suppression of annual bluegrass(poa annua) in our fairways. You may have noticed yellow spots in the fairways from time to time this summer.

These yellow spots are annual bluegrass and it's response to the PGR. The product selectively regulates the growth of the annual bluegrass more than the bentgrass, giving the bentgrass a competitive advantage.

Annual bluegrass that is growing slower than the bentgrass

Injured annual bluegrass leaves

An area that has been treated, and is currently noticeable, is in 1 fairway. This is an area of excessive overlap with the sprayer, so the injured area has received double the rate. This overlap, combined with the stress from the current weather patterns has resulted in the damage showing on the bentgrass as well.

This type of program is successful with the suppression of annual bluegrass, it will not eliminate the annual bluegrass. If this program is not continued through the season, the bluegrass will recover from the damage. This approach is a continuous effort that will be sustained from year to year in an effort to slowly reduce the population of annual bluegrass.