I removed a plug from 9 green about 10 days ago from the back right (a cold shady corner).
In the above picture the different colors are due to the mixture of bent grass and Poa. I pulled a core that had both grass species to compare how they would green up.
The thing to note is the different tissue colors and the yellow on the left edge of the plug. It is subtle but the blue/green grass blades are Bent grass. The yellow and lime green grass blades are Poa. What this suggests is the Poa may be slow to get going this spring.To survive the winter and start spring growth grass plants depend on carbohydrate reserves that are accumulated in the fall and stored in the roots. Poa has many good characteristics, however, deep rooting is not one. To explain this point I took plugs from 18 Green.
(A short history first: when we had ice damage in 2008 and had to sodded 18 green. We trenched in a drain from the low spot where ice develops to a catch basin off in the rough.
Within the trench we installed a drain tile and a length of heat tape. Each fall we have to find the end of the drain tile we buried under the green so we can have a way to drain any water that may develop under the snow. In an effort to keep the playing surface consistent we sodded the ice damaged area with Poa except for a small chunk of Bent grass which is marking the end of the drain tile under the green surface.) The following picture shows a Poa plug at the top and a bent plug at the bottom.
The interesting part is underneath the surface. The following picture shows the root zone of the Poa plug that existed at the end of October in 2009; unfortunately, fairly typical for most greens. 
This next picture is the root zone of the bent grass plug
There can be a number of different causes affecting root growth such as light availability, traffic, growing medium, fertility, soil structure and height of cut. What the two previous pictures demonstrate is the importance of grass species when it comes to root development. Remember, these two plugs were directly adjacent to one another so they would experience the exact same conditions. The only difference is one plug is bent the other Poa. Going back to this spring: with such a small root mass, Poa is not very resilient to multiple stresses. As I mentioned in the December 12 post last falls weather played havoc with the fall preparations needed to help turf overwinter in best possible condition. The plug from 9 green maybe a forewarning of what exists on the rest of the greens. The most important thing now is to get the Poa growing without any extra stress like multiple freeze thaws, ill-timed temperature drops, or early traffic.
