Weekly Express-News Article

By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist

Saturday, May 24, 2008

“Summer Blooming Shrubs”

Last summer we thought it would never stop raining, and this year it seems like it will never rain again. That is the normal pattern for South Texas. Fortunately, there are a large number of plants that can tolerate our droughts, and bloom most of the summer growing in full sun. Here are some to consider.

Esperanza is drought-tolerant, root hardy shrub with attractive light green foliage. In warmer zones, the plant will make a small tree, but in San Antonio it freezes back most winters. On typical sites it will grow to six or seven feet tall every growing season. The flowers are bell-shaped, about quarter-size and appear in clusters. They can be yellow or orange. The flowers are a nectar source for hummingbirds and butterflies. Esperanza is also deer-proof. It does not need supplemental irrigation, but blooms better if the seed pods are cut off as they form.

“Texas Gold” esperanza is the version that most nurseries now sell. I describe the “Texas Gold” variety as a blooming machine because it is an improved selection that begins blooming when the shrub is very small and keeps blooming as the shrub grows to seven or eight feet tall. One year the nursery trade even offered esperanza as a hanging basket. The rooted cuttings at one foot tall filled the container with blooms. The bloom does benefit if you cut off the small seed pods as they form.

Older varieties of Texas bells, including the orange flowered plant offer a smaller flower that appears in small clusters at the top of long stems.

Esperanza blooms in flushes like lantanas or bougainvillea. To keep the bloom heavier and more constant all summer, deadhead off the spent flowers and miniature seed heads.

Poinciana is even more drought-tolerant than esperanza. It has glow in the dark orange/yellow blooms that are favored by butterflies and hummingbirds. Unfortunately, the deer do eat poinciana. Like esperanza the stalks die back each winter and begin growth again in April. Poinciana has an airy growth habit. It also benefits from deadheading. Poinciana reaches eight or nine feet tall every growing season.

Firebush is often described as the favorite hummingbird plant in our area. Once it begins its bloom period in May, the birds in your neighborhood will find their way to the nickel-size tubular red flowers on the firebush. The blooms cover the entire plant, but firebush also is desirable because of its red bronzed foliage and disciplined growth habit. The plants will be about four feet around and six feet tall.

Like esperanza and poinciana, firebush is very drought-tolerant. At the San Antonio Botanical Garden they often plant the three together in the parking lot islands where they can expect blooms even if it does not rain all summer.

In the autumn after the first cold wave the foliage turns a purple red. Use firebush as a hummingbird attracting container plant. In a three-gallon container it forms an attractive globe-shaped shrub of about three feet around. The plant has a fibrous root system so in a container situation it loses its drought-tolerance. Expect to water it in that situation every two or three days.

Duranta is relatively new to the San Antonio nursery trade. It has purple or white blooms on the end of gracefully sweeping branches that reach seven or eight feet tall. In some winters it will die back to the roots, but my plants have not died back for the last two winters. In addition to the blooms and weeping growth pattern, the duranta is desirable because it is very attractive to butterflies and is drought-tolerant. Deer will eat duranta.

Duranta produces a large crop of yellow berries that hang on the stems all winter. They are attractive in themselves and look like they should be a desirable bird berry, but do not seem to be a favorite food source. They are eaten well after the hackberries, pyracantha, and hollies and sometime before the nandinas.

Most San Antonio gardeners think of vitex as a hot weather loving small tree that grows to 25 feet and produces two flushes of lilac-colored blooms. The new “Texas Lilac” Vitex can be used in that manner, it has deeper colored flowers and larger bloom spikes than older selections. It can also be managed as a blooming shrub like esperanza or poinciana. Cut it back each winter and in mid-summer. The plant will reach six feet tall after each cut and produce plumes of purple blooms.

Vitex is drought-tolerant, deer-proof, and does seem to have an insect or disease problems.