Poa annua: As a Friend

"I know of one club which is about to make heroic efforts to eliminate every root of Poa annua which flourishes on their greens and yet these same greens are remarkably true. This would seem to bear out the contention of one celebrated expert that Poa annua should be encouraged and not despised. He asserts that if it is not regarded as a weed but nourished and kept carefully cut, it will produce wonderfully hardy and true turf."

"That is Poa annua, a sort of outcast blue grass. It drops its seed plentifully and spreads rapidly. Maybe it would be well to try a test bed of it and give the poor old bum a real chance. He may prove a gentleman after all."
- A.W. Tillinghast, 1930s

There is no other plant that causes more controversy than Poa annua. Generally considered a weed, it is extremely adaptive to golf course conditions in the cool temperate regions of the world. Poa annua properly maintained under fairway or putting green conditions provides an excellent playing surface. Poa annua has an upright grown habit that allows the golf ball to “sit up” on fairways and provide a true ball roll on greens.

Numerous ecotypes or biotypes of annual bluegrass exist. They range from a true annual (Poa annua var. annua) which produces numerous seeds in the spring to a perennial (Poa annua var. reptans) which produces few seedheads. The ability to tolerate low mowing heights, high wear areas, compacted soil conditions, and low light conditions makes it very difficult for other cool season turfgrasses to compete against Poa annua.

If Poa annua predominates on your golf course there is a reason. Most likely Poa annua is the best adapted and most competitive grass for the given conditions and management practices. Table 1. A few general guidelines for managing Poa annua greens:

ParameterAdaption, Range, Frequency, of Parameter Comments
Mowing Height3 mm to 5 cmPoa annua can be maintained at a mowing height as low as any other cool season turfgrass. Caution: the lower your mowing height the higher the potential risk for turf loss
IrrigationGenerally, light frequentPoa annua has a shallower root system than creeping bentgrass and fescues during the summer requiring more frequent irrigation
Fertilization1.5 to 2.0 kg 100 m-2yr Foliar application of 0.05 kg 100 m-2week-1 during the summer months will reduce the likelihood of anthracnose.
TopdressingLight frequentWill keep the surface firm and reduce the likelihood of anthracnose
Aerification (coring)1 or 2 times per year (spring and fall)Not required as often as with creeping bentgrass
Major diseasesanthracnose, dollar spot, brown patch, summer patch, Typhula blight, Microdochium patch
Insect pestscutworms, black turfgrass ataenius, grubs, annual bluegrass weevil
Plant Growth RegulatorTrinexapac-ethylRepeated applications improves the summer tolerance of Poa annua

Turf n Tacos!

Find me on YouTube or twitter @brigtn

The Ohio State University Plant Science Online Certificates

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9