Hiep from Kent, Wa writes
Haven't watered the grass. Grass is dead. The summer heat has killed my lawn. I have annul bluegrass in with the dead grass. Will this help with killing the annul bluegrass if I spray tenacity over the dead grass?
Tenacity Herbicide will not control annual bluegrass so whether the lawn was currently alive or dead wouldn't make a difference in this case. If the lawn is already dead, you can spot spray the annual bluegrass with roundup. Typically, annual bluegrass cannot withstand high heat temps, so if the heat this summer has been high enough to kill or heavily damage your lawn, it should have also done the same to the annual bluegrass. If you plan to reseed your lawn this fall, then you can try using the Tenacity as a pre emergent during seeding, however it is only labeled for poa annua suppression when used as a pre, and there are other herbicides that would be better suited to preventing it from coming back. However the herbicides that do this the most effectively are also ones that would prevent your new grass from coming up, so you could not seed and use a better suited pre for poa annua in the same season.
Answer last updated on: 07/20/2021
