Poa pratensis (group)

Common Name: Kentucky bluegrass
Type: Turfgrass
Family: Poaceae
Zone: 3 to 7
Height: 0.25 to 0.25 feet
Spread: 0.50 to 0.50 feet
Bloom Time: Non-flowering
Bloom Description: Green
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium

Culture

Kentucky blue grass (hereinafter KBG) is best grown in fertile, medium moisture, well-drained soils in full sun to part shade. Prefers cool climates, neutral to slightly acidic soils, frequent watering (1-1.5" per week) and periodic applications of fertilizer (e.g., May, September and October). Full sun is best in northern climates. In Midwest Transition Area climates such as St. Louis, this grass does best with full sun in the spring and fall, but with part afternoon shade (as from shade trees) in the hot summer months. May brown up and go semi-dormant when temperatures consistently exceed 90 degrees F with periods of drought. Mow regularly to 3" tall in summer in order to provide some protection for the crowns in hot weather and to 2" tall in spring and fall. KBG is generally slow to establish and is often sold in blends with other faster growing grasses (e.g., fescues and perennial rye) which provide cover until the blue grass becomes established. For a pure KBG lawn, it is best to mix and sow the seed of 3-5 different KBG cultivars.

Noteworthy Characteristics

KBG is one of the most widely planted turfgrasses for the northern 1/2 of the United States and is generally considered to be the standard by which cool season grasses are compared. It is a creeping (by rhizomes), fine-textured, cool season turfgrass which features soft, narrow, linear, rich, medium to dark green blades (to 1/8" wide) and characteristic boat-shaped tips. The network of roots and rhizomes forms a dense sod. A large number of KBG cultivars have been introduced over the years which vary considerably in terms of disease resistance, texture, color, cultural requirements and recommended uses. 'Gnome', 'Baron' and 'Viva' seed were mixed and sown at the Kemper Center KBG demonstration plot in the Ground Cover Border. These three KBG cultivars are reportedly superior to the species. They compliment each other and as blended together provide a dense, dark green, quality turf with good resistance to disease and drought.

Problems

KBG is susceptible to a number of fungal diseases including dollar spot, leaf spots, stripe smut, powdery mildew and summer patch. Summer patch can be particularly troublesome in the St. Louis area. KBG is subject to attack from a number of insects including root-eating grubs, cutworms, billbugs and sod webworms. When under stress, most cultivars will show diminished resistance to damage from insects, diseases and drought.

Garden Uses

Turfgrass for cool to moderate climates. Home lawns, cemeteries, parks, golf courses and athletic fields.