Poa Seedheads

It's that time of year again.... The dandelions are in full bloom, the Oak pollen and Maple Samaras are pouring down out of the trees, the rough is thick and lush and the Annual Bluegrass is producing seedheads by the ton.  Annual Bluegrass or "Poa" that is producing seedheads can cause greens to become temporarily slower and bumpier during peak seedhead production.  Every year we experience the annual Poa seedhead production. However, this year seems worse than previous years. There are a few factors I contribute to this years unusual flush of seedheads. First, this spring has been ideal for Poa, COLD!  While the Poa can thrive during cool frosty conditions, bentgrass prefers warmer, sunny conditions.  During the month of April the bentgrass remained dormant, while the poa continued to grow aggressively.  This gives the Poa a competitive edge to out compete the bentgrass and dominate the putting surface.  Second, last year was an unusually cool summer and an even cooler and wetter fall.  Instead of the Poa becoming very weak and unstable during the summer months, it was able to survive and the bentgrass was unable "creep" into its space. 

 Poa is considered a weed on most golf courses.  It's many biotypes, ability to survive in most environmental conditions and its mass seed production makes it very challenging to control.  Poa is a winter annual, which begins it's life cycle with seed germinating in the late summer and early fall.  The plant matures in the fall and lives through the winter months and then produces seeds in the spring and usually dies during the heat of summer (depending on the biotype).  There are products on the market that can suppress seedhead production, however its a catch-22.  The suppression is NEVER 100%.  By suppressing the seedhead production you are actually strengthening the Poa by preventing the plant from completing its normal life cycle, which is to produce a seed, weaken and die.  The ONLY true way to reduce or eradicate the Poa population in the putting greens is to make conditions more favorable for the bentgrass.  In order to do this we would have to eliminate all shaded areas (limbing, thinning and removing trees), improve drainage and introduce newer, more aggressive varieties of bentgrass.  In the mean time we will continue to manage the Poa and try to smooth the putting surfaces out with other cultural practices; such as verti-cutting, topdressing, rolling and applying plant growth regulators.      
     

Poa seedheads almost look like broccoli