If you watch televised golf, you have probably heard the announcers talk about Poa annua, although it may have been called “Po” or “Po anna.” Poa annua – pronounced po-uh an-you-uh – is the scientific name for annual bluegrass and in the golf industry it is often referred to as simply Poa. The misconceptions about this common cool-season grass go far beyond how to pronounce its name. It frequently is viewed as an undesirable species, particularly on putting greens. However, when managed properly and grown in the right climate, this species can provide a fantastic playing surface.
In cooler regions, two grasses are commonly used on putting greens – creeping bentgrass and Poa annua. Each can exist as the only species on a putting green or as a mixed stand. Playability is usually improved when only one species is present, but a mixture of the two is far more common and can provide excellent playability and improved reliability.
Poa annua has many characteristics that make it a great putting surface, including:
- Ability to withstand traffic from golfers and maintenance equipment
- Tolerance of low-light environments and cool environments
- High density – i.e., more plants per square inch than other species
- Spike marks are less problematic due to vertical growth habit
However, there is no perfect grass species and Poa annua presents some challenges, including:
- Seedhead production
- Bumpy conditions late in the day
- Bumpy conditions during early spring
- Susceptibility to diseases and winter injury
- Vulnerability to heat and drought
Modern maintenance practices allow superintendents to manage these issues and provide excellent Poa annua putting surfaces most of the time. For example, Poa annua seedheads can be partially suppressed with the proper timing of certain plant growth regulator applications and disease can be prevented with various plant protectants. Most important to your game, bumpy conditions in the evening can be improved with plant growth regulator applications to suppress vertical growth. It is important to note that while these and other measures to manage the limitations of Poa annua can be effective, there is a significant cost associated with them.
Perhaps one of the most concerning characteristics of Poa annua is its susceptibility to winter injury. Extreme winter weather can damage Poa annua but improving growing environments and implementing various prevention strategies can significantly reduce the likelihood for winter injury.
The bottom line is that every golf course has a unique set of conditions and circumstances that dictate which grass species will perform best at their facility. Poa annua has its pros and cons, just like any other grass species, but when managed properly in the right environment it can produce some of the best putting surfaces in the world. In fact, nine of the past 16 U.S. Open Championships have been played on putting greens that were primarily Poa annua!
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