August Garden Tasks

August is deep summer in San Antonio.  Good xeriscape plants will make it through the month without supplemental watering; others will need conscientious watering to stay prosperous. Generally, no fertilizing or planting is done during this month. 

Birds and Wildlife

  • Move the hummingbird feeders to the patio. 
  • Change your sugar water every week.  Pour the old liquid in a shallow dish for the butterflies.

Shade Trees and Shrubs

  • Shade trees can reduce the heat gain in a home by 4080 percent.  
  • Cotton root rot is stimulated by hot soil temperatures.
  • This is the second-best time to prune live oak trees.  
  • If you have scale problems on your shrubs, use light summer oil.  
  • Fall webworms may appear on pecan, mulberry, ash, persimmon, and other trees. Spray Bacillus thuringiensis (B.t).
  • Windmill palm, Mexican fan palm and Sabal palm are especially well‑adapted to this area.
  • Mulch, mulch, mulch.  
  • Remember that newly-planted trees need watering once per week for the whole first season. 


  • It’s time to plant mari-mums, zinnias and sunflowers this month. Lantanas, firebush, purslane, portulaca and periwinkles are prospering in the heat. 
  • Lantana bloom can be rejuvenated with a string trimmer. 
  • Bougainvillea loves the Texas summer heat; if they’re root bound in the pot, even better.  
  • Prune the roses back.  
  • Trim back petunias and impatiens to encourage new growth.
  • Thin spring-blooming bulbs. 

Fruits and Nuts

  • Pecan trees need 1 inch of water per week over the entire root area
  • Apply borer spray to the peach trees this month.  
  • Early apples are ready for harvest.  


  • Moy Grande hibiscus produces 12-inch blooms in full sun.
  • Gold Star Esparanza produces fragrant yellow flowers clear up until frost. 
  • Stake or support larger-growing plants that have become heavy or are leaning over.

Turf Grass

  • In August, all grasses require water to stay green.  
  • When you see your footprints in the grass, it’s time to water.  
  • Grub worms eat the roots of grass plants.  
  • Chinch bugs do their damage in the hottest part of summer in the hottest part of the lawn 
  • There is still time to establish a new lawn.  
  • Remember when laying new sod; roll the turf to insure good soil‑root contact. 


  • Early August is the best time to start planting the fall garden.  Use transplants for tomatoes and peppers and direct seed corn and beans later in the month. 
  • Plant pumpkins in early August.  Get the 90-day variety. 
  • Other vegetable crops to plant in August are cucumber, eggplant, lima beans, black‑eye peas, peppers, and squash.


   Seasonal Gardening Checklist Prepared by Tom Harris, Ph.D., Honorary BCMG