Poa pratensis forms a valuable pasture plant, characteristic of well-drained, fertile soil. It is also used for making lawns in parks and gardens and is common in cool moist climates like the northeastern United States. Poa is Greek for fodder.
The name Kentucky Bluegrass derives from its flower heads, which are blue when the plant is allowed to grow to its natural height of two to three feet.
Poa pratensis is a herbaceous perennial plant 30–70 centimetres (12–28 in) tall. The leaves have boat-shaped tips, narrowly-linear, up to 20 centimetres (8 in) long and 3–5 millimetres (0.12–0.20 in) broad, smooth or slightly roughened, with a rounded to truncate ligule 1–2 millimetres (0.039–0.079 in) long. The conical panicle is 5–20 centimetres (2–8 in) long, with 3 to 5 branches in the basal whorls; the oval spikelets are 3–6 millimetres (0.12–0.24 in) long with 2 to 5 florets, and are purplish-green or grey. They are in flower from May to July, compared to Annual Meadowgrass (Poa annua) which is in flower for eight months of the year. Poa pratensis has a fairly prominent mid vein [center of the blade]
The ligule is extremely short and square ended, making a contrast with Annual Meadowgrass (Poa annua) and Rough Meadowgrass (Poa trivialis) in which it is silvery and pointed. The Kentucky bluegrass is a dark green compared to the apple green color of poa annua and poa trivialis.
There are two ill-defined subspecies:
This species is amongst the foodplants of the caterpillars of the Meadow Brown (Maniola jurtina) and Gatekeeper (Pyronia tithonus) butterflies; the Common Sun Beetle (Amara aenea) (adults feed on the developing seeds), Eupelix cuspidata of the leafhopper family, and Myrmus miriformis, a grassbug (feeds on young blades and developing seeds).
Cultivation and production
Bella Bluegrass is a cultivar produced through the breeding program at the University of Nebraska. It is unique among bluegrasses for its vegetative reproduction, slow growth habit, a short leaf.
Very dark green, compact growth habit. 'Midnight' has stood out in National Turfgrass Evaluation Program trials for 20 years. It has the distinction of heading its own class of compact-type hybrid bluegrasses known as 'Midnight-type' (crosses with 'Midnight' as a parent).
Granite is very dark green, dense and fine leaved, with exceptional turf quality and wear tolerance. It is an excellent summer performer under severe summer stress, and will persist indefinitely under demanding turfgrass conditions. Granite is a low growing cultivar that requires less frequent mowing than most other bluegrasses. Granite has shown high resistance to wilting and excellent drought tolerance for reduced water requirements.
Hybridization with Poa arachnifera
- Published: June 03, 1993 (1993-06-03). "What Makes Kentucky's Bluegrass Blue – New York Times – June 3, 1993". Query.nytimes.com. Retrieved 2012-12-23.
- Natural England description on website
- Shearman; Robert C. ; et al. "US Patent Application Poa pratensis L. named 'NE-KYB-05-001'". US Patent Office. Retrieved 27 March 2013.
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- European Poa Database
- Horticultural information on this turfgrass; growing it in the home garden
- The Observers Book of Grasses, Sedges and Rushes. Frances Rose. pages 42–43
- Kew gardens grass database