Most grass seed sold in garden centres is a mix of seeds. This is to accommodate the many conditions present in a typical lawn. Seed mixes generally contain Kentucky Blue grass for the sunny areas, Creeping Fescue for its tolerance of shady areas and drought resistance and Perennials Rye grass for it's speedy germination.
Kentucky Blue Grass (Poa pratensis)
Blue grass turf is desirable because it spreads rapidly, by under ground rhizomes, to form a dense lush carpet. Sod sold in garden centres is comprised of a blend of Kentucky Blue Grass varieties. Blue grass has good wear tolerance and is useful in high traffic areas. It requires full sunlight and ample water and is drought resistant. Blue grasses are slow to germinate, up to 5 weeks. The leaf blade is 2-4 mm wide with a boat shaped tip. Blue grass should be mowed to 2" for optimum health and vigor.
Rye Grass (Lolium perenne)
Rye grasses are used in mixes because they germinate quickly and help protect the other seeds and seedlings during their germination. Rye germinates in 1-2 weeks. Rye grass is a courser leafed plant that does not spread by rhizomes but forms in clumps. It can be distinguished by a purple tinge in the leaf sheath and its wider leaf. Rye grasses are drought resistant and tolerant of heavy traffic.
Fescue (Fescue rubra)
Fesues, Red Fescue and Creeping Fescue are used in blends for many reasons. They germinate faster the blue grass, in 3-4 weeks. They are more tolerant of drought conditions than Blue grass. They are the most tolerant of shade of any grasses. (No grass does well in heavy shade. Other perennial ground covers would be more appropriate.) They also do well in full sun. Fescues do not spread quickly and form solid mats like Blue Grasses. The leaf blade is narrow and produces a very fine textured turf. The root is deep and fibrous.
Bent Grass (Agrostis palustris)
For the golfers. This is what putting greens are made of. This is a very difficult grass to grow and maintain. Garden centres do not carry this type of seed. If you want to put your own putting green in the back yard, you will have to talk to the Greenskeeper at your club.
