You got your poa in my bentgrass!

Many Northern courses have poa annua (annual bluegrass) and bentgrass blends that comprise their playing surfaces. Despite the best efforts of turf managers, true stands of bentgrass are difficult to maintain, if not impossible. The reason? Well, we have three golf seasons in the north with two distinct types of growing conditions. Fall and spring tend to be cool and wet, while the summer is warm and dry. Voids, or bare areas in the turf will be filled with whatever grass has the competitive advantage at the time. Poa annua likes the cool and wet, while bentgrass favors the hot and dry.
Photographed are two examples of voids, earthworm castings and divots. Other types of voids include ball marks and traffic damage. As long as their exists voids in the turf during more moderate weather, Northern courses will always contend with having poa / bentgrass surfaces despite the best efforts one can afford.
These may be fighting words for turf managers who don't believe in Darwin.
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