Cutting Back Now Ensures Fall Blooms

San Antonio Express News
Sunday, August 14, 2005

Blooms may last longer in cooler climates but cooler climates do not have the potential for two spectacular bloom periods each year as South Texas does. Most of us expect our flowering perennials to bloom well in the spring but overlook the best possible season for bloom – – fall. Remember, plants are not flowering to make us happy; they are flowering to produce seed and complete the reproductive stage of their life cycle. If the old flower stalks are cut off and not allowed to mature seeds, the plant will attempt to make more seed. Then we get to enjoy another bloom cycle.

Hot weather greatly shortens the life and beauty of blooms. During the spring bloom season, Texas weather is making the transition from winter to summer. Unfortunately the transition period may only be for several days, i.e., Texas temperatures rapidly change from frosty to scorchy. The fall weather conditions, in comparison, are ideal for blooms. Usually extremely hot weather ends in September and the cooler temperatures, especially at night, signal that the South Central Texas second “spring” has begun. These cooler temperatures stimulate plant growth and intensify the color and duration of the blooms. Many people do not prepare their plants for this second spring so they miss really the most spectacular bloom period.

August is the time to act. Remember, shrubs that bloom after June usually do so from buds that are formed on shoots that grow the same year. These shrubs should be pruned in late winter to promote vigorous shoot-growth in spring. Examples of shrubs that bloom on current season’s growth include: Buddleia David or B. globosa (buddleia or butterfly bush), Hibiscus Moscheutos (Perennial hibiscus such as ‘Moy Grande’, ‘Flare’, ‘Red River’), Hibiscus Rosa-Sinensis (Chinese Hibiscus), Hibiscus syriacus (shrub althea), Hypericum spp. (St. Johnswort), Lagerstroemia indica (crapemyrtle), Rosa spp. (roses), Tecoma stans or Esperanza and Vitex. There are many examples of flowering perennials which should be cutback to encourage reblooming. Fall-blooming perennials, such as Salvia greggii and S. farinancea, Mexican marigold mint (Tegetes lucida), chrysanthemums, and Salvia leucantha, should have been pruned periodically during the summer to keep them compact–if you didn’t do that pruning, cut them back by one-third as soon as possible. Perennial or Summer Phlox (Phlox paniculata) such as ‘John Fanick’ or ‘Victoria’ should be cut to the ground and allowed to resprout with new stems.

To stimulate rapid re-blooming and more and larger flowers, one pound (1 cup) of a slow-release formulation of lawn fertilizer (19-5-9) should be scattered around each large plant or in a 100 square foot planting area after pruning. For cutting-back specifics for each of the above-mentioned plants, go to: and see the third column under the August listing entitled: “Cutback Now To Ensure Fall Blooms Later”. There are more details about rose pruning for the fall and how to make cut-flowers last longer.

So take action now to insure that you don’t miss our second spring and the beauty of the flowers which can adorn it.

Dr. Jerry Parsons is a Professor for Texas A&M University and a Texas Cooperative Extension Horticulturist for over 30 years in South Central Texas. For more information on this or other horticulture topics, go to and our County Extension website at

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