• Kentucky bluegrass is not native to North America, but it is grown extensively to use as forage for grazing livestock, as well as for landscape sod on many American lawns. It is a cool-season, long-living perennial grass. It grows best during cool, moist weather in fertile, well-draining soil, but it is adaptable to poorer soils and high heat by going dormant. Bluegrass can survive several months without significant rainfall and will quickly bounce back when moist, cool weather returns.
  
  

Growth Habit

• The growth pattern for Kentucky bluegrass is dependent upon the daylight hours, not average daily temperatures, which means that more shoots are produced during the short days of early spring than during the long summer days. Grass used for forage can grow 18 to 24 inches tall.
  
  

Rhizomes

• Kentucky bluegrass spreads by rhizomes---thick, fleshy roots---to form a dense sod. Rhizome growth proliferates in the spring, ceases in summer when temperatures exceed 80 degrees Fahrenheit, and resumes again in the fall. A rhizome's lifetime is no longer than two years. High nitrogen fertilizer and close, frequent mowing greatly reduces rhizome growth.
  
  

Shoots

• New shoots are produced in the late spring and early summer. In the spring and summer, the shoots stand upright, but are less upright in the early spring and fall. Some shoots turn downward and develop into shoots beneath the soil as branch shoots of other rhizomes.
  
  

Blades

• Blades have a characteristic boat-shaped leaf tip and can grow 18 to 24 inches tall when used as fodder. It is important to keep mower blades sharp when mowing bluegrass because dull blades split the tips. Split blades quickly turn brown, even if the grass is healthy and has not yet gone dormant. Leaf blades remain for 10 to 12 days, according to Texas A&M University, and one shoot has three to four leaves at a time. Blades that appear early in the season are 3 to 4 inches in length, and those that appear later in the season are progressively shorter.