We have some contamination of poa out into our zoysia/bermuda areas outside the collars. When the poa is small, its not a problem from a playability standpoint but once it starts to grow and gets larger in size, there are issues with these clumps. A short term cure that we are trying is to reduce a walk mower to .75" which helps to cut off the clump and flatten it out. Our intermediate cut mower which goes around this area normally is set at an 1 3/8" which does not reduce the affect of the clump. We are also doing some spot spraying of these clumps to reduce their competitiveness. We also hope the work we are doing to improve some of the zoysia will help the zoysia grow allowing it to compete with the poa as well. Heat will also help reduce the competitiveness of the poa. Early August this season, we will be treating these areas to reduce the amount of poa that germinates from these areas.
The picture above shows the collar cut on the left 1/3, the 3/4" cut in the middle and the taller 1 3/8" cut on the right side. If you enlarge the picture, you can see how the mowing helps to reduce the clump of poa to a size that will help with playability.