Bluegrass is the most popular type of grass in North America because it produces a beautiful, lush and finely textured lawn. Bluegrass is usually combined with rye-grasses because it has a later green-up period. It has the ability to develop a good root system against drought because it's a fast growing grass. The grass blades are tender so it tends to need higher rates of water and fertilizer.  Because of rhizomes growth, it can quickly recuperate from foot traffic injury.  Kentucky Bluegrass is a cool-season grass and it grows best durning the fall, winter and spring months. Once the weather begins to get warmer, growth slows down. Kentucky bluegrass can tolerate shade but it grows best in full sun. On the downside, Kentucky bluegrass can be susceptible to weeds and other lawn diseases such as thatch, so it is usually mixed with ryegrass.