Originally a tropical grass, St. Augustine is now found growing in most parts of the United States and Canada with ease. This hardy grass spreads quickly to fill moist and shaded area with thick growth. St. Augustine also grows in marshes, swamps and lagoons, and even coastal areas because it can withstand salt. Some homeowners, however, may want to remove this type of grass to grow another type. There are several ways of achieving that.
Mow the lawn prior to removing it. This makes it even and level, and easy to reach the roots. Keep it at a height of 1 to 1 ½ inches.
Remove patches of St. Augustine grass manually, specially if it grows in small areas. Use a sod cutter or a shovel to dig the ground deep enough so it can reach the roots as well. Although this technique is the most labor intensive, it is the safest as opposed to using chemicals, and guarantees the best results, since the grass comes out with its roots.
Spray or pour a systemic herbicide (one which spreads through the vascular system of the plants) to patches of St. Augustine grass as an alternative to removing it manually. These herbicides are easily available in most garden supply centers. Make sure the entire patch is covered with herbicide, which will kill the lawn in 10 days to 2 weeks.
Spread a black or deep blue tarp over the grass as an alternative to using herbicide or removing it manually. Make sure you cover all the edges. Weigh the edges down in place with heavy stones or landscaping rocks. The strong rays of the sun will bake the grass as well as the roots.
Collect the grass with a rake and put it in a wheelbarrow or tarp to dispose appropriately.
Dig up tiny patches of St. Augustine lawn grass instead of the entire lawn with a hand held shovel. Insert it into the ground at an angle, push it down and then slice it up so you get the roots as well.