University of Maryland Extension

Roughstalk bluegrass

Roughstalk bluegrass
Poa trivialis

Roughstalk bluegrass
(Photo credit: Perdue University Turfgrass Program: Turf tips 5/2008)

Lighter colored Poa trivialis in a darker tall fescue lawn

(More lawn weeds)  (Control Options)  (General Weed Gallery)

Life Cycle: perennial, cool season grassy weed. 
Growth habit: forms light green patches that are evident early in the season. They can turn brown and go dormant in the heat of the summer. Grass blades can look shiny.
Reproduction: by seed and stolon(above ground runners) formation. Prolific seeder. 
Conditions that favor growth: thrives in poorly drained, compacted soil, shade. Will move into sunny areas of the lawn. Spreads aggressively. 

Cultural control: Maintain healthy, dense turf that can compete and prevent weed establishment.
Mechanical control: Small infestations can be dug out; must remove all parts of root. Then reseed. 
Chemical control: Perennial grasses growing out of place in lawns are extremely difficult to control selectively in turfgrasses. Cannot be effectively controlled by any of the herbicides currently on the market. Total lawn renovation or killing the patches using glyphosate and then reseeding will slow it down but because of the vast seed bank in the soil, it will return. 

For a glossary of herbicide terms and additional information see: control options 

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