Poa annua–or just Poa–is known in the U.S. as annual bluegrass or annual meadow grass. It is a type of grass that can be found on golf courses throughout the west, such as Pebble Beach, Torrey Pines etc., and used on putting greens.
Poa is a member of the bluegrasses, of which there are as many as 500 species.
Poa annua is by far the best known of the Poas to golfers due to its use for popular putting surfaces. Many of the country’s most famous courses in the west utilize poa grasses.
Remember this putt from Tiger Woods at the 2008 U.S. Open? It was putted on Poa grass:
Putting greens with Poa annua are sometimes streaking or patchy looking because Poa annua has so many different strains and the more strains that grow on one putting surface the streakier/patchier it will appear (see photo above).
However, the affect is only cosmetic, and does not impact on the quality of a putting surface that uses Poa annua in terms of how smooth it is. There’s a reason the grass is a popular one for some of the world’s most famous golf courses.
Poa annua has one quality which some golfers are not fans of. Different Poa annua strains grow at different rates of speed during the sunniest part of the day, causing the greens to roll at various speeds. Putts like this will also bounce around more.
Also, during the springtime, poa grasses tend to bud and these buds create less than ideal surfaces (i.e. bounces….).
Poas used for greens usually have high shoot density with fine leaf texture. They usually can persist whether in the sun or the shade. However, the Poa can be susceptible to diseases and has a low tolerance for stress.
Watch this awesome video from the USGA explaining Poa:
Managing greens with Poa annua means extensive amounts of mowing. The one biggest factors on a golf green with Poa is the grass seems to become accustomed to the specific height it is mowed and kept at.
Poa on greens sometimes become puffy, which requires vertical mowing so that it will be corrected and the green will perform better. It is thought that the puffiness is due to extremely high shoot densities that end up buckling the surface of the green instead of buildup of organic and thatch matter.
When applying fertilizer to Poa, liquid is likely the best to use as it can be applied more evenly and will not leave spots or freckles on the green.
Maintenance of Poa greens can be very challenging but a well maintain one ends up being a beautiful asset to any golf course.