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How to Manage Pests

The UC Guide to Healthy Lawns

Kentucky bluegrass — Poa pratensis

Photo of Kentucky bluegrass
Illustration of boat-shaped tipIllustration of leaf blades of Kentucky bluegrass
Boat-shaped tip and parallel-sided leaf blades


Kentucky bluegrass is a cool-season grass that grows best during the fall, winter, and spring months when temperatures are cool. Its growth slows during the warm summer months. Kentucky bluegrass prefers full sun, but will tolerate some shade. This species is used widely throughout the U.S. where it is well adapted, but it has a poor summer performance in California in areas with warm to hot temperatures. When stressed by temperatures, lack of water, or poor soils, Kentucky bluegrass can be susceptible to disease and weed invasion. For a more disease resistant turf that offers good color and year-round performance, Kentucky bluegrass is often mixed with perennial ryegrass. Usually 2 or more cultivars of each species are used and it is recommended that at least 15% of the mixture is perennial ryegrass.

Identifying tips

A dark-green, medium-textured turf. The new leaves are folded in the bud, there are no auricles, and a short, membranous ligule is present. The leaf blades have a boat-shaped tip; the sides of the blades are parallel, giving a stiff appearance. This species spreads by underground rhizomes that can self-repair injured, worn, or damaged spots. Kentucky bluegrass produces a dense turf.


Moderate to high maintenance. It can tolerate cold winters but has a relatively low tolerance for heat and is only moderately drought tolerant. During the summer months if stressed for water, Kentucky bluegrass can go dormant. It has moderate wear tolerance, recovering quickly from some abuse.

Illustration of collar of Kentucky bluegrass
Illustration of overall plant of Kentucky bluegrass
Overall plant structure of Kentucky bluegrass Collar of Kentucky bluegrass

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