How to Control Annual Bluegrass

Identifying Annual Bluegrass

Weed. Just reading the word makes you cringe. They are insidious, sneaky, relentless, and a constant plague on gorgeous turf. Some threats occur year round, and others like Annual Bluegrass AKA Poa annua, occur as regular as clockwork. Landscape managers and lawn enthusiast know this threat well. 1 to 3 inches long, boat shaped leafs, that characteristic crinkling part way down. It is most noticeable in closely mowed lawns. With a Spring mid-season death you end up with bare patches during the height of sports season. No matter how short you cut it, it can produce seeds as low as 2mm in height. There are some options to combat the annual bluegrass scourge.

Combating Annual Bluegrass

On new lawns/courses or after a renovation the best option is to remove the Annual Bluegrass. This can be done with a knife. Although time consuming and expensive, this is still one of the very best options for Poa control. If the resources are present it should be considered as a first response. Because of Annual Bluegrass’s biodiversity, and literally 1000’s of genetic variations, it has been incredibly difficult to find a single herbicidal solution.

Depending on your enviornment and grass type, certain herbicides can prove effective. Progress can be used following a massive overseeding, but only on perennial ryegrass fairways. Mesotrione is only effective on Kentucky bluegrass and kills other grass types. Bispyribac-sodium can be effective on creeping bentgrass, though not without yellowing. Available in 2016, PoaCure inhibits cellular wall growth in Poa and works on multiple strains. Testing has shown promise.

One of the most effective solutions is Roundup Ready creeping bentgrass. Developed by a team-up between Scotts and Monsanto, this grass is resistant to Roundup. Poa annua is not. Studies have shown that this genetically selected creeping bentgrass strain is almost identical physically to standard creeping bentgrass. Though it has not been released yet, it is only a matter of time before this strain makes it to market and solves the Poa annua problem, at least for a little while.

For more information on Pao Annua and what grass seed is right for you, contact your local turf experts.