''Poa pratensis'', commonly known as Kentucky bluegrass (or blue grass), smooth meadow-grass, or common meadow-grass, is a perennial
species of grass
native to practically all of Europe, North Asia
and the mountains of Algeria and Morocco. Although the species is spread over all of the cool, humid parts of the United States, it is not native to North America
. The Spanish Empire
brought the seeds of Kentucky bluegrass to the New World
in mixtures with other grasses. ''Poa pratensis'' forms a valuable pasture plant, characteristic of well-drained, fertile soil. It is also used for making lawn
s in parks and gardens and is common in cool moist climates like the Pacific Northwest
, and Northeastern United States
. When found on native grasslands in Canada, however, it is considered an unwelcome exotic plant, and is indicative of a disturbed and degraded landscape.
''Poa pratensis'' was one of the many species described by Carl Linnaeus
in his landmark work ''Species Plantarum
'' in 1753. ''Poa'' is Greek
and ''pratensis'' is derived from ''pratum'', the Latin
. The name Kentucky bluegrass derives from its flower heads, which are blue when the plant is allowed to grow to its natural height of .
''Poa pratensis'' is the type species
of the grass family Poaceae
There are two ill-defined subspecies:
*''Poa pratensis'' subsp. ''pratensis'' – temperate regions
*''Poa pratensis'' subsp. ''colpodea'' – Arctic
''Poa pratensis'' is a herbaceous
perennial plant tall. The leaves
have boat-shaped tips, narrowly linear, up to long and broad, smooth or slightly roughened, with a rounded to truncate ligule long. The conical panicle
is long, with 3 to 5 branches in the basal whorls; the oval spikelet
s are long with 2 to 5 floret
s, 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).
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/blue compared to the apple-green color of ''Poa annua'' and ''Poa trivialis''.
is creeping, with runners (rhizome
s). The broad, blunt leaves tend to spread at the base, forming close mats.
This species is among the food plants of the caterpillars of the meadow brown
(''Maniola jurtina''), gatekeeper
(''Pyronia tithonus''), and pepper-and-salt skipper
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).Natural England description on website
Cultivation and production
Since the 1950s and early 1960s, 90% of Kentucky bluegrass seed in the United States has been produced on specialist farms in Idaho, Oregon and Washington.
During the 1990s botanists began experimenting with hybrids of ''Poa pratensis'' and Texas bluegrass (''P. arachnifera''), with the goal of creating a drought and heat-resistant lawn grass.
It is famously used for the playing field of Lambeau Field in Green Bay, WI and is sown into the field for reinforcement.
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File:Poa pratensis (3883809159).jpg
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File:Poa pratensis sl6.jpg
File:Poa pratensis detail.jpeg|Closeup of flowers
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File:Poa pratensis seeds 20101113.jpg
Flora Europaea: ''Poa pratensis''
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
Category:Grasses of Africa
Category:Grasses of Asia
Category:Grasses of Europe
Category:Grasses of North America
Category:Grasses of Canada
Category:Grasses of the United States
Category:Plants described in 1753
Category:Taxa named by Carl Linnaeus