Bluegrass refers to a genus of grasses, some of which look bluish when in flower. The term often refers to a particular species, Kentucky bluegrass, Poa pratensis, that is commonly grown in central Kentucky and in lawns throughout the eastern United States.
The cereal grasses, e.g., wheat, rice, corn, oats, barley, and rye, provide the grain that is the staple food of most of mankind and the major type of feed.
The grasses also include most of the hay and pasture plants, e.g., sorghum, timothy, bent grass, bluegrass, orchard grass, and fescue.
Popularly the word grass is used chiefly for these latter and for the lawn grass types; it is also loosely applied to plants which are not true grasses (e.g., clover and alfalfa) but which are similarly grown.
Bluegrass develops a shallow root system and is not a high drought tolerant grass, but it has the ability to go dormant in severe situations and can recover if watered intermittently keeping the lawn minimally growing during drought.
This grass has successfully spread across half of the United States and into Canada and is well known as a pasture grass for horses, cattle, and sheep throughout the areas of adaptation.
Bluegrass seeds are easy to harvest and has developed into one of the species with the largest number of varieties of any grass seed.