Wednesday, December 23, 2009

Winter weeds?

Back to golf course information. I am sure a lot of you have noticed the emergence of a small lime green winter weed on the greens lately. This weed is called Poa-Annua and thrives during November through May or when the temperatures get below 50 degrees. The higher temperatures we get around May (80 degrees or above) will finally kill it. But this is not a desirable weed on a green when the turf it'self goes dormant (or any other time). Poa-Annua generally has two germinating periods in our area, around November-December and again around February. There are two different ways of killing it, the first is with a pre-emergent herbicide which sets up a barrier on top of the soil which will kill the tender shoots as they try to grow through it, and a post-emergent herbicide which you spray over the top of the plant and is absorbed through the leaf tissues. Due to cost issues, I prefer using a post-emergent chemical around January that actually has some pre-emergent effect, which will keep it from germinating during the second period. We will be spraying our greens during the first or second week of January (weather permitting). After this spraying it will take three weeks for the plant to totally die off. Until then we will be cutting the greens a little more often.
You will also see these same weeds germinating throughout the golf course. Due to cost issues we may or may not be able to kills these weeds also.