Common Name: bluegrass, rough
Species: Poa trivialis L.
Bayer Code: POATR

Rough (also called roughstalk) bluegrass has a relatively limited adaptation as a turf species because of intolerance to heat, drought, and traffic. It is also very patchy in appearance and therefore does not perform well in mixtures. However, rough bluegrass is sometimes used alone or in combination with perennial ryegrass for winter overseeding of golf course putting greens. Rough bluegrass can often be confused with Kentucky bluegrass. One way to distinguish them is to examine the root structures: rough bluegrass has stolons (above ground) and Kentucky bluegrass has rhizomes (below ground). Another way to distinguish between them is that rough bluegrass has a long, pointed membranous ligule and Kentucky bluegrass has a short, even membranous ligule.
rough bluegrass
[Click on image to view plant details]
rough bluegrass ligule
rough bluegrass leaf tip
rough bluegrass
rough bluegrass
Seedhead / Flower panicleseedhead is a panicle with flattened spikelets with 2-3 seeds each
Vernation Type foldedleaves folded in the bud
Ligule Type membranoussharp pointed, entire, may be hairs along the edge, 0.16 - 0.24 inches (4 - 6 mm) long
Growth Season / Life Cycle cool season turf OR perennial weed 
Auricle Type absent 
Leaf Blade Tip Shape boat shapedflat, sharply creased, glossy, edges rough at least near tip; two distinct, clear lines, one on each side of the midrib
Leaf Blade Width narrow, less than 0.1 in OR medium, 0.1 - 0.2 in0.04 - 0.16 inches (1 - 4 mm) wide
Stolon Presence present 
Rhizome Presence absent 
Collar Type divideddivided by midrib, distinct
Sheath Margin openopen part way only
Sheath Type flattenedsheath is usually rough; sharply creased