Roughstalk Bluegrass

Biological Name:

Poa trivialis (Roughstalk-Bluegrass)

Natural Habitat:

Roughstalk-Bluegrass: Wet meadows and fields, North America


Roughstalk-Bluegrass is a tall grassy weed that grows in fields and along roadsides. It has long narrow leaves and small spike-like flowers that are blue in color. It is often found in areas with poor drainage and can spread quickly if not controlled.

Frequently Asked Questions (FAQs)

Q: How do you get rid of rough bluegrass?
A: Rough Bluegrass as a Weed Digging or removal with hand or mechanical equipment, for example a sod cutter, is one way to control undesired perennial turfgrasses. You may spot treat an infested area with an appropriate non-selective herbicide, realizing it will also kill the desired turfgrass.

Q: Will bluegrass spread on its own?
A: Unlike bunch-forming grasses, such as tall fescue and ryegrass, Kentucky bluegrass is a self-spreading, sod-forming grass. Once established, it spreads readily via underground stems known as rhizomes to form a dense, thick turf. This aggressive growth habit gives KBG the capacity to recuperate quickly from damage.

Q: How do you thicken Kentucky bluegrass?
A: Fall is a good time to pull them up and reseed where they once were. Doing this will allow your lawn to grow back thicker in those areas, hopefully choking out any weeds that try to grow back.

Q: Should you Dethatch bluegrass?
A: Kentucky bluegrass should be dethatched in the spring (April) or fall (Sept.) when it is actively growing and never in the summer. Zoysiagrass, on the other hand, should be dethatched in the summer when it is actively growing.

Q: Does rough bluegrass spread?
A: Rough bluegrass spreads through stolons (it puts out shoots over the top of the ground). Stoloniferous grasses tend to grow and spread more aggressively, like Bermuda, zoysia, or St. Augustine grasses do.

Q: Why is my bluegrass turning brown?
A: Kentucky bluegrass can start turning brown after about 7 days without water. This browning appearance is the grass going into dormancy in order to survive the drought. Some leaf tissue will die, but the base and roots of the grass are still alive and will green up when water returns.

Q: Will bluegrass choke out quackgrass?
A: Unfortunately there is not an herbicide that would kill the quackgrass without damage cool season turf, such as Kentucky Bluegrass.

Q: How do I get rid of POA Trivialis?
A: In many cases, the most effective way to control Poa Trivialis is to use a broad-spectrum herbicide like Roundup to kill the Poa Triv — and, in the process, your lawn. Then, re-seed the lawn and start anew — Poa Trivialis-free!

Q: What Scotts product kills poa annua?
A: A single application of Scotts WeedEX Prevent with Halts in the early spring can prevent crabgrass and other problem weeds as listed. Controls the following weeds: crabgrass, foxtail, spurge, barnyardgrass, fall panicum, goosegrass*, henbit, chickweed, poa annua, corn speedwell and oxalis (common yellow woodsorrel).

Q: Will scarifying get rid of poa?
A: Scarifying/Raking By raking or scarifying your lawn, this will identify where the POA is. POA can be obvious by its colour but it can also be identified by its horizontal growth. When raking and scarifying, this will stand up the POA which is currently laying horizontally.

Q: What is the difference between poa annua and Poa Trivialis?
A: Poa annua is an annual grass, that spreads by dropping seeds in the lawn each summer. Poa trivialis (or rough bluegrass) on the other hand is similarly light green in color but it’s a perennial plant that comes back year after year once it initially makes its way into your yard.

Q: What herbicide kills poa?
A: Even if you applied a pre-emergent on time, it’s good to apply a post-emergent to kill any current Poa annua weeds before they begin spreading—and they can spread pretty fast. A few Poa annua killers are Hi-Yield Atrazine and Tenacity. Revolver is also a good option.

Q: Will poa annua go away on its own?
A: Removing an unwanted cool-season grass, like poa annua, from a desirable cool-season grass, like Fescue, is very hard to do without damaging both grasses. For Fescue lawns, it is best to let Mother Nature do the work. Once temperatures reach the 80’s or above consistently, poa annua will naturally die out on its own.

Q: What causes poa grass?
A: Poa annua (annual meadow grass) is an annoying, weak plant, a weed that germinates and flowers at low temperatures. In reaction to drought, the plant experiences stress causing it to form and spread huge numbers of seed heads. The number of seeds produced by Poa annua can quickly amount to hundreds per plant.

About the author

Samuel is a gardening professional and enthusiast who has spent over 20 years advising homeowners and farm owners on weed identification, prevention and removal. He has an undergraduate degree in plant and soil science from Michigan State University.