Bluegrass

The Kentucky bluegrass  is generally described as a perennial..This is not native to the U.S.and has its most active growth period in the spring ,summer,fall. w4
http://www.gardenguides.com/

The Bluegrass State is the common nickname for Kentucky because of the vast expanses of Bluegrass across parts of the Commonwealth. Bluegrass is not really blue. It's green. In the spring, however, when seen from a distance, the blue-purple buds of Bluegrass lend a bluish tint to the landscape.
http://www.netstate.com/states/intro/ky_intro.htm

http://wonderwise.unl.edu/15pollen/kidsactivity/media/microscope_pollen/e-pol-bluegrass-plant.gif