How to Kill Fescue Grass in a St. Augustine Lawn

St. Augustine lawns become infested with cool-season grass types such as fescue. Because fescue grows in bunches, it breaks up the uniform creeping texture of St. Augustine grass. Also, fescue is a perennial weed, which means that it cannot be controlled with a selective herbicide without harming this grass. Gardeners must use a broadleaf herbicide to kill the fescue and lay St. Augustine sod in bare areas to prevent weed growth.

Shovel
Herbicide
Tiller
Fertilizer
St. Augustine sod

Instructions

- 1
  Press a shovel 2 to 3 inches away from fescue grass and at a depth of 6 inches to remove the root systems. Dig up fescue growing in areas next the ornamental flowers or trees where you do not want to use herbicide sprays that can harm nearby vegetation.
- 2
  Spray fescue grass with an herbicide that contains glyphosate when you have a 48-hour window of dry weather. Glyphosate needs 48 hours to absorb into the foliage of fescue to inhibit the weed's ability to produce proteins.
- 3
  Reapply the herbicide in 10 to 14 days to ensure the fescue is dead. Dig up dead areas of fescue grass. Burn or throw away the debris.
- 4
  Till the bare patch of soil. Work a starter fertilizer high in phosphorous into the first 2 to 4 inches of top soil.
- 5
  Lay a piece of St. Augustine sod over the bare areas. Cut the sod with a trowel, so that it fits over the bare patch. Water the soil side of the sod and lay over the bare area. To lay two pieces of St. Augustine sod next to each other, butt the sides of the sod together to prevent cracks.

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