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How to control Poa annua on your lawn

The best way to control Poa annua is by applying a pre-emergent herbicide during the fall. Poa annua typically germinates during late summer or early fall. Therefore, you have to target it before the first shoots emerge. But there are also other factors to consider.

Poa annua, commonly referred to as annual meadow grass, annual bluegrass, or just Poa in some regions of the US, is a tough weed to control.

It produces hundreds of seeds at once, which can lay dormant in the soil for years without any activity, and then one day sprout all at once, causing a huge problem.

When should I get rid of Poa annua?

The best time to control Poa annua is during fall, just before it begins germination. Poa annua generally sprouts during the early stages of fall, just as the warm summer temperatures start to drop.

The best time to use a pre-emergent herbicide in the fall would be in early September. If you plan to apply it in the spring, the best time would be in early March, just as the temperatures start to rise again.

Note: These time ranges may differ from one region to the other. Check your local weather for information about the start and end of each season.

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How do I control Poa annua?

To control Poa annua, apply a pre-emergent in the fall to prevent the seeds from sprouting and then a post-emergent in the spring to kill any Poa annua that might have gotten past the pre-emergent.

What herbicides kill Poa annua?

Since Poa annua grows from the seed stage every year, you need a pre-emergent that stays in the soil for six to twelve weeks, destroying any of its seeds.

Take the extra step to apply pre-emergent two more times in the fall, to manage the weeds in winter since they still have the ability to withstand the cold.

Make the first application early in September and then another 30 days later. Getting the right timing is crucial for it to be effective.

The following herbicides are effective for eliminating Poa annua:

1. Tenacity

Tenacity Herbicide

Is ornamental grass seed germinating on your lawn? If so, Tenacity will help you eliminate Poa annua without hurting your ornamental grass.

Tenacity is recommended because it is safe to use even when your ornamental grass seeds are sprouting, and it will not harm them.

If you intend to seed your grass in the fall, use this product to eliminate annual blue grass, which sprouts alongside lawn grass.

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Apply it thrice, starting in late September or early October, and leave a two-week period in between applications for best results.

2. Revolver herbicide

Revolver herbicide

Revolver is best if you have Bermuda grass on your lawn. The herbicide kills Poa annua weeds in Bermuda grass within a few days.  

Always practice care while using this product, especially in areas with temperatures higher than 60 degrees F. You should also follow the manufacturer’s instructions regarding using the product in cold weather.

To use Revolver, mix 0.2 to 0.4 fluid ounces per 1000 square feet of lawn and per gallon of water.

How do I get rid of Poa annua naturally?

Natural ways of eliminating Poa annua include:

  • Hand pulling: Practical in small lawns. Make sure that when you pull, you are doing so firmly and from the root so as to take out the whole thing. Otherwise, Poa annua will sprout again in a few days.
  • Apply mulch: Use it around your ornamental grass to prevent the weeds from getting to it. Although effective, this method might be slow.
A plant growing through mulch
Photo by: Flicker/Kathy

How do I identify Poa annua?

You have to identify poa annua properly in order for you to apply the appropriate measures.

Poa annua weed
The Poa annua weed.
  • Stem: Grows anywhere from 15 to 25 cm tall and has a slightly flat structure. The pinnacle is triangular and is open at the top, measuring 5 and 7.5 cm long.
  • Flowers: Stalked with a smooth hairless surface. They grow to about 1 or 2 cm long when mature. The root system of this plant is fibrous.
  • Leaves: Characterized by blunt tips with serrated edges and smooth surfaces, and appear to be soft and drooping. The growth at the intersection between the stem and leafstalk is bright and pointed compared to common meadow grass and Poa trivialis, whose intersections are squared.
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