Knowledgebase
Poa Annua #885451
Asked September 16, 2024, 2:52 PM EDT
Kalamazoo County Michigan
Expert Response
Hello,
Given your situation, here are some recommendations for managing post-emergent Poa annua in your perennial rye lawn:
Spot Treatment with Mesotrione (Tenacity):
While Tenacity can cause temporary bleaching in perennial ryegrass, it is effective against Poa annua. Given your overseeding date (August 18th), you can use Tenacity as a spot treatment to minimize damage to your lawn. The bleaching effect is usually temporary, and the grass should recover.
Post-Emergent Herbicides:
Since you have been using a SpeedZone/Quinclorac blend, continue spot-treating with this combination. It is effective against various broadleaf and grassy weeds, including Poa annua.
Pre-Emergent Herbicides:
As you mentioned, Prodiamine is a good option but requires a 60-day wait after overseeding. You can plan to apply it later in the fall or early spring to prevent Poa annua from germinating next season.
Cultural Practices:
Maintain proper mowing height and avoid overwatering, as Poa annua thrives in moist conditions. Deep, infrequent watering is more beneficial.
Non-Chemical Control: (I have to add this as an option – HA HA!)
Hand-pulling can be adequate for small infestations. Ensure you remove the entire root to prevent regrowth.
Halosulfuron for Yellow Nutsedge:
Continue using halosulfuron for yellow nutsedge control. It is practical and won’t interfere with your Poa annua treatments.
Given the average first frost in your area is about a month away, focusing on spot treatments and cultural practices now will help manage the Poa annua without causing significant damage to your newly overseeded lawn.
Here is the reference from MSU on Poa annua:
Annual Bluegrass - Turf (msu.edu)
If there is something I am missing, please let me know!
I hope this helps!