Annual bluegrass, or
Poa annua, is a turf type that is found on golf course throughout the United States. The amount of
Poa varies greatly depending on the location and microclimates of any given golf course. In fact, annual bluegrass is the predominant turf species on many golf courses throughout southeastern Wisconsin. While
Poa can be a great playing surface at times, it lacks the hardiness of its more desirable counterpart creeping bentgrass. This was on display at this year’s U.S. Open at Chambers Bay when both competitors and the media alike had less than pleasant things to say about the putting surfaces. Annual bluegrass struggles during hot summer days due to its shallow root system and is more susceptible to damage to damage during cold and icy Wisconsin winters.
One reason that Hidden Glen’s putting surfaces are so pure is the fact that only a small amount of
Poa annua has infiltrated the creeping bentgrass. The lack of shade and drainage afforded by the sandy soil base of the putting surfaces are major contributors to the near
Poa-free putting surfaces. In 2015, we have applied more aggressive growth regulators to the putting greens that foster bentgrass growth at the expense of the Poa.
If you have played recently, you have likely noticed the small green circles on #1 green ranging in size from slightly larger than a ball mark to the size of a silver dollar. These circles are areas where the golf course maintenance staff has physically removed the annual bluegrass. The purple flags in the attached picture identify the annual of bluegrass prior to its removal. Due to its shaded environment, reduced air movement and lack of sun, #1 green is particularly susceptible to
Poa annua encroachment and many small patches had taken hold. An aggressive approach of manual removal was required in order to keep the
Poa out. These areas will fill in with creeping bentgrass in conjunction with the aerification recovery.