Q: What do you think about Tenacity or Poa Constrictor to remove annual bluegrass from my lawn?

A: Both products are used by professionals and both are available to homeowners, though they are expensive. That said, you have to be very careful to read and follow the label on each one. They can be used on some lawn grasses but not others and timing the application correctly is important. You have to be REALLY careful with mixing. Remember that “annual” bluegrass is a misnomer. There are biotypes that behave more as a perennial plant and some are resistant to these products. There is no silver bullet.

see Controlling Poa annua in Sports Turf