Choosing the right grass for your lawn can seem complicated. It's something you'll have to live with for years to come, and planting or reseeding a lawn is an expensive endeavor. You've got to consider the region in which you live; how well a type of grass can withstand heat, cold, drought and flooding; how well a grass can withstand weeds; and then there's always the issue of how much money you are willing to spend. Even common grasses can be expensive.
Cool Weather Grass
Annual ryegrass is also known as Italian ryegrass. It holds up in winter relatively well, but does not deal well with drought and heat. Because of its somewhat ragged appearance it's often used as a temporary groundcover interspersed with other species of more permanent grass. Bentgrass is a species that survives in very low climates, but requires copious amounts of water to resist insects and diseases in summer. This species is often used for golf courses because it can be cut short and takes on a fine, delicate appearance when done so. Left long, it makes a decent cold-weather grass for homes and landscaping, though it must be edged frequently as it propagates aggressively. Rough bluegrass is a species that can only thrive in cool, moist conditions. Despite the name, the leaves are a pale green and tend to lie flat if not mowed frequently.
Kentucky bluegrass is one of the most common grasses which grows in both hot and cold weather conditions to create high-quality lawns. It fills in bare spots, but it can go dormant in summer if there is insufficient moisture and it cannot tolerate shade at all. Zoysiagrass is an Asian species which grows well in the United States. It's both salt- and drought-tolerant, but is not able to withstand drought well. It produces a deep and complex root system, but is slow to grow, so repair to damaged lawn areas can take months. Tall fescue is a derivative of Kentucky bluegrass. It has better drought-resistance and shade tolerance, and is a good choice for high-traffic lawns.
Hot Weather Grass
Bahia is a southern species which thrives in Florida. It can withstand extreme heat, insects, disease and drought. Unfortunately, it grows in ragged and is slow to fill in bare spots, so lawns can appear inferior when compared to St. Augustine grass. St. Augustine grows quickly, and is all-around resistant, but cannot handle months without rain like bahia can. Also, St. Augustine is expensive and very difficult to obtain it in seed form because it does not propagate very quickly. Another downside is that it produces a great deal of thatch, so the lawn will require more maintenance.