How to Prevent Poa Annua (Annual Bluegrass)
Now is the time to put down a preventer to keep Poa Annua (Annual Bluegrass) from germinating this fall.
Lawn weeds like Poa Annua (Annual Bluegrass), Common Chickweed, and Henbit are “Winter Annuals”. This means they germinate in fall, thrive in spring and then die during summer, but not before scattering seed so the cycle can start all over again in fall. (“Summer Annuals”, like Crabgrass, Foxtail and Barnyardgrass, have the opposite cycle of germinating in spring, thriving in summer and dying just prior to winter, but not before scattering seed so the cycle can start all over again in spring.)
If you vowed last spring that you wanted to stop these winter annual weeds from invading your lawn, you need to pick up a bag Scotts Halts or Scotts Turf Builder with Halts so you can treat your lawn now. (One of the Halts products is the correct product to use even though it says to apply in spring to prevent crabgrass.) Be sure to water after application.
Caution: If you are planning to plant any grass seed this fall, you should not spread weed prevention in those areas as it will keep your good grass seed from germinating.