Texas Natives – October, 2007
When the extremes of heat and drought prevail upon the garden, there are a few plants that dare to be indifferent. White-thorn acacia or mescat (Acacia constricta) is one the native plants that performs its best during the extremes of a Texas summer. Whitethorn acacia is native from West Texas through the southwestern U.S. and into Mexico. It is also considered one of the most cold-tolerant of the native acacia species.
A small, deciduous tree, it attains a maximum height of 18 feet and an equal spread. Any well-drained soil site in full sun will successfully accommodate white-thorn acacia. Usually late to leaf out in spring, the delicate bipinnately compound grayish-green foliage contributes to the overall ethereal stature of this tree. Small, sweetly fragrant blazing yellow puffballs of flowers adorn plants in mid-summer on new growth, followed by the slender reddish to dark brown seed pods. Most plants are armed with conspicuous ashen-colored spines on old wood, hence the name white-thorn. It has been reported that thornless varieties exist in the wild at higher elevations. The bark color ranges from dark brown to reddish-purple, and along with the white thorns, can provide landscape interest during winter months. Although shrubby in appearance when young, pruning plants to several trunks can enhance the mature form of the tree.
White-thorn acacia flowers are an excellent nectar source for bees, butterflies and other insect pollinators. The seed is consumed by several species of birds and small mammals. It provides important nesting, roosting and breeding habitat for many native bird species. The foliage is not a preferable browse for deer, rabbit, sheep or cattle, but will most likely be consumed when other vegetation is scarce.
It can be utilized as a landscape specimen tree, a barrier hedge, or for wildlife habitat. A long-lived, slow-growing tree, white-thorn acacia will bloom intermittently depending on available moisture from spring until fall. White-thorn acacia is usually available at retail nurseries specializing in native plants and is well-adapted to survive the toughest of water restrictions.
Texas Discovery Gardens at Fair Park has a specimen white-thorn acacia in the Benny J. Simpson Native Plant Collection. The gardens are open Monday through Saturday from 10 a.m. until 5 p.m. Visit
www.texasdiscoverygardens.org for more information.
About the author: Tina Dombrowski is the Director of Horticulture at Texas Discovery Gardens at Fair Park, Dallas. She has a particular interest in Texas native plants, butterflies, pollinating insects and their interconnected histories.