Poa Annua can drive you crazy because of it’s lime green color which is easy to notice in a well cared for lawn. However, it germinates in the fall and very few products can kill it so it can be difficult for many to address. Poa Annua will also die off in summer heat, but not before going to seed. So you’re left with bare spots and plenty of seeds for the next crop to come in.
To kill Poa Annua you want to use Tenacity, but most importantly you’ll want to put a pre-emergent like prodiamine down in the fall before Poa Annua begins to germinate – before the soil temperature reaches 70 degrees. Some even will skip the Tenacity and let it naturally die from the summer heat or the winter cold and simply focus on preventing the next year’s batch from coming in.
Before you pull out the Tenacity, it’s important to notice the differences between Poa Annua and Kentucky Bluegrass. Many people will over spray their lawn trying to kill Poa Annua when it’s actually KBG. Watch this video to see the difference: