Poa Annua

What is it?

Poa Annua (also known as ‘annual meadow grass’ or ‘annual bluegrass’) is a turf weed that is commonly found in lawns, golf courses and sports fields.

It's an incredibly adaptable weed, known to survive in harsher conditions like colder climates & shaded areas. You can identify Poa Annua by its distinct bright green blades growing horizontally in distinct clumps/ tufts. It will likely differ in colour to your pre-existing lawn. They also may have a white, floral-looking seed head that blooms in spring.

The white seed heads of Poa Annua can look very similar to flowering Rye grass, so make sure you know the difference to avoid confusion. Poa Annua seed heads will be loose, open and have multiple tiny flowers along the branches. Rye Grass will be more compact, dense, and greener in colour. They will also have larger seeds and a bristle-like appearance.

When do they flower?

March-June.

Treatment and Control

Culturally

Use a hoe or garden trowel to dig up and remove the plant- be sure to remove the entire plant including the roots, to prevent regrowth. 

You can also follow these steps to control the spread/ prevent growth of Poa Annua: 

• Maintain the correct mowing height for your lawn, regular mowing and lawn maintenance will encourage the growth of desirable grasses, rather than Poa Annua. 
• Fertilise your soil/garden according to its needs. Over-fertilising can encourage Poa Annua due to the high levels of nitrogen, so regularly check your soil PH levels and fertilise accordingly.

Chemically 

There are many different weed killers available for Poa Annua on the market, however it depends on how heavily affected your turf is and the growth stage of the weed. 

You can use pre-emergent weed killers to control and prevent seed germination and establishment, which will remove the spread of Poa Annua before flowering. This is best used in the late summer/ early autumn before the seeds begin to germinate. 

You can also use a post-emergent herbicide when Poa Annua is actively growing to control the spread, though re-application my be needed for total eradication of the weed. 

You should apply Glyphosate sparingly with a sprayer (be wary of overspray), sponge or paint brush. Glyphosate is very strong and will kill all surrounding vegetation if not applied effectively. Only use on targeted weed area to ensure precise weed control and minimised lawn damage. 

When using weed-killers, it is important that you follow the required safety precautions and reads the labels carefully.

Did you know?

• Online Turf’s Rye Gold and Stadium turf are guaranteed weed-free on delivery, so you won’t have to worry about any weeds appearing in your newly laid turf.
• Ancient Romans used Poa Annua as a medicinal herb to treat inflammation and fevers. They also used it as fodder for livestock.