Poa in the spring...

For a few reasons, we always deal with smoothness issues on the greens in the spring.  Unfortunately, this year the ball may be hopping a bit more than we've seen in a while. With last fall's aerification holes still being visible, it's easy to blame them as the main cause; and while the aerification holes may be part of the issue, it appears that the bigger culprit is the Poa annua in the greens.  

As most golfers know, Poa goes to seed this time of year.  We make preventative growth regulator applications to suppress this process, since less seed equals smoother greens in the spring.  The timing for these sprays is based on a Growing Degree Days model--basically a measure of heat accumulation.  

It appears that this past winter's weather threw a curveball into this predictive model for us, and resulted in much less seed suppression than we typically achieve.  One possibility is that despite below average temperatures, the insulation from the prolonged snow cover kept the Poa on pace for seed production.   

As you can see above, the greens are comprised of a combination of both Creeping Bentgrass along with multiple biotypes of Poa annua, which are currently growing at very different rates.  This lack of uniformity in grasses adds another wrinkle to the smoothness challenge. 

With the greens being cut at 1/10" in height, it may be hard to believe that one area is actually higher than another on the putting surface.  And at 1/10" it's a bit challenging to take a picture that shows the difference of Bent vs Poa.  However, if we look at an approach, it may be easier to visualize the difference on two types of grass being cut the same.

In the photo above, it's pretty easy to see how the clumps of Poa rise above the still semi-dormant Bentgrass, even when precisely cut with a reel mower.  A ball rolling across this surface will tend to have a little hop to it. 

In order to address the issue on the greens, we have decided to fumigate, strip and reseed the putting surfaces to Bentgrass--just kidding.  We have actually been lightly verticutting and topdressing them, but having a bit of patience may be the best thing we can do at the moment.  The Poa seed will soon end.