Most of the cool season grasses that begin growing early are not native to Wisconsin prairies. Bluegrass can be distinguished vegetatively from other early grasses by its narrow blade, which is V-shaped in cross section, and by the leaf tip, which is shaped like the bow of a boat.
Kentucky bluegrass is distinguished from Canada bluegrass by the shape of the stem.
Kentucky bluegrass was previously thought to be indigenous to the mountains of the Northeast along the Canadian border. However, it was introduced as a cultivar from Europe, and has been bred into multiple cultivars since its introduction. Because of its extensive use for lawns and in pastures, it is common in most grasslands, even those managed for native species. Canada bluegrass is also naturalized from Europe. Their effects on the natural systems are equivalent and therefore should be treated as one problem.