Poa in Full Bloom.

You often here the term poa on golf courses but few actually know what it is or how it can affect daily play. Annual bluegrass (Poa annua L.) is a very common grass species that almost every golf course in North America has. It's very adaptable and can be found on all areas of the golf course including rough, fairways, tees and greens.

In nature,  poa behaves as a true annual. It germinates in spring and/or fall when moisture is adequate and develops quickly, often flowering six to eight weeks after germination. After flowering and setting seed, these annual types die typically from drought and leave dormant viable seed behind to germinate when moisture again becomes available. This efficiency in seed production makes annual bluegrass (poa) a major component of the seed bank of cultivated soils. This seed can remain dormant in the soil profile for up to 6 years.

Many high end golf courses go to great lengths to eliminate Poa. It's a labor intensive, time consuming and expensive practice. So why do it?  Here is a list of the Pros and Cons of Poa annua.

CONS:  -Inconsistent putting speed and roll on the golf green.

               (Greens are slower and do not roll true)

              -Mottled appearance and not aesthetically pleasing to the eye.

                (Poa is light green in color compared to darker green hues of bentgrass)

              -Temper mental growth habit.

                (Does not tolerate too hot, too cold, to wet or too dry conditions)

              -Prone to environmental and cultural stress.

                (Compaction, disease, surface disturbance, traffic, ice and freeze injury,
                  etc.)

             

PROS:   -Usually the first grass to break dormancy from winter.

              -Can provide a true and beautiful putting surface when conditions favor it.

                (ie. Pebble Beach and Oakmont are 100% Poa greens)

              -Naturally reproduce with prolific seed dispersal.

                (Under lush conditions, 14,000-63,000 seeds/ft2/year)

              -Thrives under normal cultural practices.

                (Regular top dressing, verti-cutting and aerating practices)



Poa Seed Heads #6 Greens Collar (June 12, 2011)



My philosophy with regards to poa is one that differs from the high end courses in Alberta. I have a limited budget and work force and accept poa as a fact of life on the course. Over the years I have incorporated bentgrass (A-4) after each core aeration. Currently our greens comprise approximately 60 to 80% poa. It's at this time of year the greens take on a whitish color due to the seed heads. This process will cease in another 3 to 4 weeks and then the greens will take on a darker green most golfers have come to appreciate.  







Poa on #6 Green (June 12, 2011)

 To combat the rougher putting surface the seed heads cause, I lightly topdress the greens on bi-weekly cycles. This helps fill in the voids within the turf canopy and will speed up and smooth out the green. At times this process gets delayed during prolonged periods of wet weather. It's best to topdress the greens during dry conditions so that the sand can be matted in more efficiently. This process is so unobtrusive, golfers don't even know when the greens have been topdressed.

Poa Seed Head (Left) vs. Bentgrass (Right)
(Notice difference in leaf texture and width)



Over the next few years, I plan on over-seeding the greens more often then I do. The addition of our new greens over-seeder the club purchased this month will help immensely in bringing poa populations down to acceptable levels. I am aiming for 40% poa levels but this will take many years to accomplish. We will never be 100% poa free and once a club accepts this, dealing with this overly sensitive grass species will save a lot of time, money and energy. Poa is here to stay so work with it and provide the best possible playing conditions the golf course can financially afford.