Watching the 2017 Waste Management Phoenix Open this past weekend was quite entertaining, especially watching the thousands of fans who fill the stadium like bleacher seats around the 16^th hole.  For me the tournament also focuses my attention more on the agronomics.  Specifically, how far we have come regarding winter overseeding bermudagrass greens.

Looking at the history of winter overseeding, perennial ryegrass was the choice decades ago on the coarser more open bermudagrass varieties.  The key to getting a quality putting surface with perennial ryegrass was to seed at a high seeding rate forcing the plant into prolonged juvenile state that allowed for green’s height mowing.   Some golf courses at the time didn’t really like the quality of perennial ryegrass and would substitute or mix creeping bentgrass in to provide a finer quality turf.  The dis-advantage to creeping bentgrass was that the grass would not transition (or die) in the spring suffocating out the bermudagrass when it broke winter dormancy.  Years of using creeping bentgrass resulted in the warm season greens becoming entirely creeping bentgrass!

 With the advent of the ultra-dwarfs and their immediate precursors in the mid- 1990s the use of perennial ryegrass became impractical due to the size of the seed.  You could not work the perennial ryegrass seed down through the canopy.  Rough bluegrass (Poa trivialis) became a popular overseeding turf in part due to its relatively fast germination, and small seed size (comparable to Kentucky bluegrass seed). 

As time has marched on we have now seen winter overseeding mixes evolve from 100 percent Poa Trivialis to mixes that include percentages of velvet bentgrass cultivars, creeping bentgrass cultivars breed for poor heat tolerance, and in some instances a little fine fescue.  These blends are often designed around the golf course superintendent and courses recommendation.  So now many of those beautiful uniform overseeded greens may be a complex array of various cool season turfgrasses.