Smooth Meadow-grass
Encyclopedia
Poa pratensis, commonly known as Kentucky Bluegrass, Smooth Meadow-grass, or Common Meadow-grass, is a perennial species of grass
native to Europe
, Asia
, and northern Africa
.
.
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.
The rootstock
is creeping, with runners (rhizome
s). The broad, blunt leaves tend to spread at the base, forming close mats.
Poa pratensis is a herbaceous
perennial plant 30 – tall. The leaves
have boat-shaped tips, narrowly-linear, up to 20 centimetres (7.9 in) long and 3 – broad, smooth or slightly roughened, with a rounded to truncate ligule 1 – long. The conical panicle
is 5 – long, with 3 to 5 branches in the basal whorls; the oval spikelets are 3 – 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.
Poa pratensis is the type species of the grass family Poaceae
.
There are two ill-defined subspecies:
(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).
, Oregon
and Washington.
), with the goal of creating a drought
and heat
-resistant lawn grass.
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
native to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, and northern Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
.
General description
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 fodderFodder
Fodder or animal feed is any agricultural foodstuff used specifically to feed domesticated livestock such as cattle, goats, sheep, horses, chickens and pigs. Most animal feed is from plants but some is of animal origin...
.
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.
The rootstock
Rootstock
A rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...
is creeping, with runners (rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s). The broad, blunt leaves tend to spread at the base, forming close mats.
Poa pratensis is a herbaceous
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
perennial plant 30 – tall. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
have boat-shaped tips, narrowly-linear, up to 20 centimetres (7.9 in) long and 3 – broad, smooth or slightly roughened, with a rounded to truncate ligule 1 – long. The conical panicle
Panicle
A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....
is 5 – long, with 3 to 5 branches in the basal whorls; the oval spikelets are 3 – 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
Poa annua
Poa annua, or annual meadow grass , is a widespread low-growing turfgrass in temperate climates. Though P. annua is commonly considered a solely annual plant due to its name, perennial bio-types do exist. 'Poa' is Greek for fodder. It is one of the sweetest grasses for green fodder, but less ...
) which is in flower for eight months of the year.
Poa pratensis has a fairly prominent mid vein [center of the blade]
The ligule
Ligule
A ligule — is a thin outgrowth at the junction of leaf and leafstalk of many grasses and sedges or a strap-shaped corolla, such as that of a ray floret in plants in the daisy family....
is extremely short and square ended, making a contrast with Annual Meadowgrass (Poa annua
Poa annua
Poa annua, or annual meadow grass , is a widespread low-growing turfgrass in temperate climates. Though P. annua is commonly considered a solely annual plant due to its name, perennial bio-types do exist. 'Poa' is Greek for fodder. It is one of the sweetest grasses for green fodder, but less ...
) and Rough Meadowgrass (Poa trivialis
Poa trivialis
Poa trivialis , is a perennial plant, and is regarded in the USA as an ornamental plant and is of the Poa family.-Description:...
) 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.
Poa pratensis is the type species of the grass family Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
.
There are two ill-defined subspecies:
- Poa pratensis ssp. pratensis – temperate regions
- Poa pratensis ssp. colpodea – Arctic
Wildlife value
This species is amongst the foodplants of the caterpillars of the Meadow BrownMeadow Brown
The Meadow Brown, Maniola jurtina, is a butterfly found in European meadows, where its larvae feed on grasses, such as Sheep's Fescue.Similar species are Gatekeeper and Small Heath ....
(Maniola jurtina) and Gatekeeper
Gatekeeper Butterfly
The Gatekeeper sometimes called the Hedge Brown is a common butterfly in the United Kingdom. It is a member of the subfamily Satyrinae in the family Nymphalidae. A similar species is the Meadow Brown; the two species can be difficult to distinguish with closed wings since underwing markings are...
(Pyronia tithonus) butterflies; the Common Sun Beetle (Amara aenea
Amara aenea
Amara aenea is a ground beetle common in almost the whole Europe and Northern Asia. Its range covers also parts of Northern Africa. It is known as the common sun beetle....
) (adults feed on the developing seeds), Eupelix cuspidata of the leafhopper
Leafhopper
Leafhopper is a common name applied to any species from the family Cicadellidae. Leafhoppers, colloquially known as hoppers, are minute plant-feeding insects in the superfamily Membracoidea in the order Hemiptera...
family, and Myrmus miriformis, a grassbug (feeds on young blades and developing seeds).
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 IdahoIdaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
and Washington.
Hybridization with Poa arachnifera
During the 1990s botanists began experimenting with hybrids of Poa pratensis and Texas bluegrass (P. arachniferaPoa arachnifera
Texas bluegrass is a species of grass.-Hybridization with Kentucky bluegrass:During the 1990s, botanists began experimenting with producing hybrids of Texas bluegrass and Kentucky bluegrass for use as a drought-resistant lawn grass and wintering foraging plant for grazing livestock...
), with the goal of creating a drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
and heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
-resistant lawn grass.
Further reading
- 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