Manage for creeping bentgrass or manage for poa annua? This is the ultimate questions that Superintendents ask themselves and is an industry wide topic. A topic that will probably never be resolved. Many say if you have poa annua manage it. Well we've had poa dominant fairways before and let me tell you they're really not that fun to manage. Now that we've been managing for creeping bentgrass, to me the answer is quite clear.
A perfect is example is on our fairways. I probe fairways quite frequently and one reason is I love looking at our bentgrass roots. They are DEEP! I on average I find our roots to be 12-18" deep. Deep roots equal less water, less fertilizer and all round healthier plants. Also by watering deep and infrequently we can provide firm playing conditions as we are able to stretch the length between water cycles. We also have less thatch on the fairways. We are able provide conditions that are adventitious for deep roots which also equals less fertility and that allows us to stretch our fertility applications and as a result have less thatch on the fairways as the roots are going deep and are not limited to the top 4 inches.
Our poa roots, on the other hand are shallow. Shallow rooted plants need to be babied and require a great deal more TLC. As you can see in this photo, poa annua roots are only 4" deep compared to the 12" roots of the creeping bentgrass. Moisture levels at 12" soil depths are very good. Right where the creeping bentgrass roots extend. Heading into the heat of the summer we can all sleep a lot better knowing if the roots are deep and healthy so will be the playing surfaces.