Meadow grass is a common term used to describe grasses found in open fields and pastures. While often used as a general descriptor for any grass species growing in a meadow, the term most frequently and scientifically applies to members of the Poa genus. This large group of cool-season grasses, known in North America as bluegrass, is foundational to lawns, sports fields, and livestock forage across temperate regions.
Defining Meadow Grass
The concept of meadow grass functions on two levels: a broad ecological description and a narrow botanical classification. Generally, a meadow grass is any non-woody plant, often a grass, that dominates an open habitat or field. These areas are typically semi-natural grasslands maintained by limited human intervention, often for hay or livestock production.
The specific botanical reference is the Poa genus, which encompasses about 570 species globally. The name Poa is derived from the Greek word for ‘fodder,’ reflecting its history as a food source for grazing animals. These species are characterized as cool-season grasses, meaning their peak growth occurs in the spring and fall. Many Poa species are perennial and exhibit a rhizomatous growth habit, spreading horizontally via underground stems to form a dense sod.
Key Species of Meadow Grass
The most significant species in the Poa genus is Kentucky Bluegrass, scientifically named Poa pratensis. This perennial grass is the most widely planted cool-season turfgrass in the United States, valued for its rich, dark blue-green color and its capacity to form a dense sod. Its primary method of spread is through creeping rhizomes, which allow it to self-repair and withstand heavy foot traffic on lawns, golf courses, and athletic fields.
Another widespread and often problematic species is Annual Bluegrass (Poa annua), which is one of the most common plants in the world. Despite its name, this species can be an annual or a short-lived perennial, capable of producing large amounts of seed even when mowed very short. It is frequently viewed as a weed in cultivated turf due to its lighter, yellowish-green color and tendency to die out in hot summer weather, leaving bare patches.
Rough Bluegrass (Poa trivialis) is a third notable species, known for thriving in moist, shady conditions. This perennial grass spreads by above-ground runners called stolons, forming thick mats of light green foliage. Unlike Kentucky Bluegrass, it is shallow-rooted and susceptible to drought and heat, often going dormant and turning brown during the summer.
Habitat and Ecological Role
Meadow grasses are adapted to various environments but generally flourish in cool-season climates with adequate moisture. The optimal soil conditions for many Poa species include fertile, well-drained loams or clays, though some types can tolerate poorly drained sites. They require full sun to light shade, with species like Rough Bluegrass showing a preference for partial shade.
In the broader ecosystem, meadow grasses fulfill several functions, particularly in human-managed landscapes. They serve as primary forage plants for livestock, making them components of hay and pasture mixes. The extensive root systems of perennial species like Kentucky Bluegrass are effective at controlling soil erosion and absorbing storm water runoff. These open habitats also provide cover, nesting sites, and food for wildlife, including birds, insects, and pollinators.
Identification and Cultivation
Identifying a Poa species often relies on inspecting the leaf structure. The leaf tips of most meadow grasses are shaped like the prow of a small boat or canoe, which distinguishes them from many other grass genera. Additionally, the young leaves of Poa species emerge from the shoot folded flat, not rolled. The upper leaf surface sometimes displays two faint grooves running parallel to the midrib, often called “tramlines.”
For cultivation in lawns and pastures, Poa species are cool-season grasses that require specific management. Kentucky Bluegrass tolerates close mowing and requires consistent moisture and periodic fertilization to maintain its dense color. Rough Bluegrass requires high soil moisture to prevent browning during warm periods. To establish a new meadow, reducing soil fertility is often recommended, as this prevents vigorous grasses from outcompeting desired wildflowers.