What is Poa Annua?

If you've noticed an unsightly grassy weed invading your lush lawn, it may well be poa annua, also known as annual bluegrass. This light green, coarse-textured grass can be an annual nuisance or a perennial problem, spreading aggressively through its prolific seed production. Here's what you need to know about identifying and controlling this stubborn weed.

What is Poa Annua?

Poa annua is a type of grass species belonging to the Poa genus. It is called "annual" because it completes its life cycle within one year, although in some cases, it can act as a perennial. This grass is often considered a weed in lawns and golf courses due to its rapid growth and ability to thrive in a variety of conditions. Here are more defining characteristics: 

• Grassy with a light green color and coarse texture
• Germinates in fall, goes dormant over winter, and resumes growth in spring
• Spreads rapidly by seed, with a single plant producing hundreds of seeds
• Creates unsightly seedhead clumps in lawns

Getting Rid of Poa Annua

Controlling poa annua without harming your desired grasses is challenging, but an integrated approach can be effective:

Natural Control Methods

• Proper mowing, irrigation, and fertilization to promote thick turf
• Core aeration to reduce compaction and improve grass vigor
• Overseeding to establish dense grass stands

Chemical Controls

• Apply poa annua pre-emergent herbicides (e.g. Dimension, Barricade) in early fall
• Spot treat with poa annua post-emergent herbicides in spring
• Rotate modes of action to prevent resistance

Combination Approach

• Use pre-emergents in fall and post-emergents in spring for best poa annua killer results
• Maintain good lawn care practices to promote vigorous turf growth
• Be patient - it may take multiple years of integrated poa annua control efforts

Living with poa annua can be frustrating, but with diligent cultural practices and well-timed use of pre- and post-emergent herbicides, you can regain control of your lawn. Consistency is key when battling this pesky weed.