A. In the Texas Gulf Coast, the most common grass used is St. Augustine grass.  It is a warm-season grass, which grows in humid part of the United States.  St. Augustine grass is a shade-tolerant grass, however, it requires some sunlight for grass to be able to grow.  The reason for a St. Augustine lawn receding is a lack of sunlight.  The light that is needed by grass is absorbed by the trees, so root depth decreases, photosynthesis is reduced, and the grass becomes more susceptible to disease.  Mature trees alter the temperature, decrease wind, increase humidity, and competes with grass for water and nutrients.  The result is poor lawn performance.

1) The first thing you can do is to increase the mowing height of your turfgrass up to 3.5 inches in dense shade.

2) When you fertilize your lawn, you can reduce nitrogen fertilizer in dense shade to prevent succulent growth that is more susceptible to disease.

3) By selectively pruning the tree limbs of trees shading your lawn, you will increase sunlight to your St. Augustine grass.

4) If you have shallow-rooted trees, then root pruning can also improve your lawn.

5) If you like to keep your mature tress with dense canopies, and if this is an essential part of your landscaping, then the other option you have is to cover the ground underneath the trees with shade-tolerant ground cover, such as Asiatic jasmine or English ivy instead of turfgrass.