Some of you may have noticed the yellow spots appearing in South fairways mostly along the edges of the fairways. These yellow spots are a variety of weed grass known as Poa annua, in contrast to the 007 Bentgrass which was seeded into the fairways during the renovation in 2006-2007. The yellowing is occurring due to aggressive applications of a plant growth regulator which encourages the growth of bentgrass and discourages the growth of Poa annua.
Our goal is to maintain a pure stance of 007 Bentgrass, but due to the stubbornness of Poa annua it is expected to be a continuous battle that we will face. Poa annua thrives in cool wet weather such as we are experiencing now, while 007 Bentgrass tends to slow growth and become less competitive. For this reason, now is a good time to utilize growth regulators aggressive against Poa annua, although, when the summer heat begins and 90 degree days occur we must back off on our applications so that we do not begin damaging the bentgrass. There are some other products entering the market that may be more successful in Poa annua elimination but have not reached full production and may involve a higher rate of risk.