Roots

What goes on above ground is directly related to what is happening below ground. You cannot have good quality putting surfaces without a dense and healthy root system. Roots are the heart of any turf stand. They provide water and nutrients to the shoots of the grass plant. So superintendents are continually talking about roots.

Annual bluegrass (many of you refer to as poa) is notorious for weak and shallow roots, particularly when the shoots are constantly chopped off at .100 inches ... or less. The South greens are predominantly annual bluegrass. The newer bentgrasses were developed with a much denser and vigorous root system, allowing the shoots to tolerate closer mowing and leading to faster and smoother putting surfaces. The South practice green is comprised of L93, A1 and A4 bentgrasses with some minor annual bluegrass encroachment.

This photo shows the difference in rooting depth between the newer variety PG bentgrass plug (left side and center) and an older annual bluegrass core from #9 green (on the far right). The bentgrass roots extend into the native soil and the annual bluegrass roots do not. The deeper root system provides a better putting surface.