Poa Greens and Springtime

Well it has been quite a spring so far.  The coldest recorded March since 1931, and an April that has seen 90 degrees along with a very late frost this morning.  It is certainly hard to determine what mode the grass is in, much less determine what practice to employ next.  It is always this time of year that our greens undergo a radical change; poa seeding time.

Poa annua is labeled a winter annual, although for our greens it becomes a perennial that seeds every year. Poa is one of the rare plants that can seed at the heights we mow greens.  Our attempts to control seedheads is based on several environmental factors.  We use models that use a method called degree days.  These have been developed by several universities and others that use minimum and maximum temperatures to determine the optimum seeding time, or as we refer to it the pre boot stage.  In conjunction we look at blooming of other species and our gut feel for the best timing to apply growth regulators that may inhibit the seeding.

As with most things in nature there is no absolute.  Fluctuations in winter weather, storms and rains can all change this equation.  Additionally the products we use are useful in this process, but offer no guarantee for  success.  In fact, many times we have had good success, only to see the seed heads slowly and sporadicly pop out all summer long.  As I like to point out,  Nature finds a way.

Obviously putting quality suffers when the surface get bumpy, and seed heads create an uneven surface.  Many question if we have changed our mowing heights or practices.  The short answer is no, heights are the same as usual, in fact we increase the amount of rolling in hope of smoothing the surface.  Due to the dissimilar growth rates of poa and bent grass, we see little grass when mowing and most of it is poa seed heads.  Usually after our aeration, temperatures begin to rise, seeding season subsides and the greens start to resemble the condition we see the rest of the year.

In the picture shown, the darker purple areas are bent grass, which as you can see comprise only a small  percentage of our greens surface.

We work hard to manage our poa greens to withstand the stress of the seasons, and this includes understanding the effects of all practices performed.  Poa seeding isn't fun for anyone, but trying to change the plants natural instincts can have adverse effects the rest of the season.  We continually research products, university trials as well as discussions with other superintendents to evaluate our process in the hopes to continually improve conditions for all seasons.