There are countless species of wild grass, with different varieties growing in different regions. Most grasses can be classified as either bunch grass, which grows in tight clusters of shoots, or sod grass, which forms a solid carpet of foliage. Wild grasses come in numerous colors, ranging from nearly-red to nearly-blue, and there are species adapted for almost every pH level and degree of moisture.
Wild grass will often naturally sprout up in your lawn, particularly when the soil is dry. Most wild grasses can survive dry conditions better than domestic grass, and will begin to take over when the grass intentionally planted is weak. The new species of grass will likely be a different color or texture than your existing grass, and can give your lawn a mottled appearance.
Wild grass can be combated simply by ensuring that the domestic grass has ideal growing conditions. Fertilizing the lawn, deep and infrequent watering, and mowing at a height of approximately 2½ inches can all prevent a wild grass takeover. Chemical herbicides are also effective at destroying wild grass, though domestic grass may have to be replanted after application.
Sometimes the best option is to embrace nature instead of fighting it. Growing wild grass in your lawn is easier than growing domestic grass and tends to be better for the immediate environment. Wild grasses usually require less water and hence can often stay green all year long without external assistance from sprinkler systems. Native grasses improve the strength and quality of the soil, as well.