About 80 percent of my 10,000 square foot lawn is Poa annua. Do I need to start over by killing everything, tilling, soil prep and replanting seed? Or, is there a gradual way to regain control? If I do kill and totally redo the lawn, when and how do I do that, since I allow the grass to go dormant during the winter?
Welcome to life in western Oregon. In fact, 100 percent of golf courses in western Oregon and western Washington are almost 100 percent Poa, even though they did not plant it. The key is the maintenance practices.
Poa annua maintenance
If you want a nice lawn, mow consistently, fertilize a few times a year, and irrigate consistently in the summer. Keep in mind, you can mow annual bluegrass down to 1/10 of an inch, which is what golf courses do for putting greens. I am not suggesting you do this, but it will easily mow at 1.5 or 2 inches. The key is you need a smooth surface so mow consistently across your lawn at the same height. When you mow it lower, the grass gets denser and the leaf blades get thinner so your lawn looks nicer.
You can spray it out and start over, but you will be fighting Poa again from the start and your seed bank is now loaded with its seed.
Good luck.
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Use pesticides safely!
- Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
- Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
- Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.
