Everything You Need to Know About Maintaining Your Yard This September
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Everything You Need to Know About Maintaining Your Yard This September

September 06 2023

By Karen Shook, Harris County Master Gardener

Apologies for stating the obvious, but as I am writing this in mid-August, it is miserably hot and dry. While September is historically cooler than August, the forecasts continue to say temperatures will be above average for the next several months (Note, I use the past 25 years for “average”). Let’s hope they are wrong. In the meantime, I've been using my indoor time studying options for rain dance moves.

I know you are keeping your beds mulched. Remember the mantra, check for “too wet, too dry, just right” and water accordingly. Remember a good, deep watering is better than frequent, light watering.

Perennials and Ornamental Grasses

  • Some spring flowering perennials can be divided (daylilies, calla lilies and irises). Others should wait until it is a bit cooler (Shasta daisy, gaillardia, cannas).
  • When the weather cools a bit, celebrate fall by planting chrysanthemums for fall color. Fertilize every 2 - 3 weeks until flower buds appear, then once a week until buds show color.
  • You can also plant perennials, ornamental grasses, groundcovers, and vines. Prepare the soil first! Fertilize the new plants. Established plants can be fertilized in September, then pause until February.


  • Start seeds for cool season like snapdragons, stock, calendula, alyssum. They will typically be ready for transplant in six to eight weeks. You can start the hardening process once two sets of leaves appear.
  • Pansies can be planted now for color into spring.


  • Refrigerate tulip and hyacinth bulbs by late September to give adequate chill time for December planting.


  • Roses (other than once blooming) that were not pruned in late August, should be pruned in early Sept. Reduce size by 1/3 (or to desired height) making cuts just above a bud. Remove dead wood, diseased canes, twiggy growth. Fertilize and water after pruning. Continue regular fungicide spray schedule.


  • Check soil acidity. Many plants prefer slightly acidic soil and Harris County tends toward alkaline. Acidify as needed especially for acid loving azaleas and camellias.
  • Red tip photinias sheared early in the month should give a nice show with colorful new growth in cooler weather.
  • Prepare beds for planting shrubs in October.
  • Mid-to-early fall is a good time to take semi hardwood cuttings for plants you want to save in case of severe winter weather or plants you just want to share.


  • Plant bluebonnet, Indian paintbrush seeds in early fall. Scarified bluebonnet seeds germinate more quickly. Rake them gently into the ground.

Edibles (vegetables, herbs, berries, fruits)

  • It is time to plant most cool weather vegetables (after weather cools a bit, but not so late in September that we have a freeze before veggies are ready to harvest). Check your seed packet to estimate timing.
  • It is a good time to plant strawberries if you can find them. Fertilize the soil prior to planting.
  • See the following link for recommended planting times: Harris County Vegetable Planting Guide


  • Light pruning of lower branches and some inner branches may be needed to let the sun through to lawns and plants below the trees.
  • September is often an active month in hurricane season. Make sure you don't have any dead branches waiting to fall.

Source: Harris County Master Gardeners Urban Dirt Newsletter (September 2023 Edition)

About Urban Dirt

Each month, Harris County Master Gardeners publishes an informative, resourceful newsletter entitled "Urban Dirt". This article was derived from the September 2023 edition. To read the September 2023 edition of this newsletter, click the button below.

URBAN DIRT - September 2023 EDITION

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