Texas Mountain Laurel

Sophora secundiflora

Right away I want to suggest a new name for this plant. In fact, I believe many people already refer to this plant by this name, which has spontaneously arisen in the folk taxonomy.

Ok, maybe it’s not so spontaneous. I mean, if you saw a plant like this, with wisteria-like flowers that droop like grapes on a grape vine, and the distinctive pungent aroma of grape Kool-Aid is all about, would you NOT call such a plant “Grape Kool-Aid plant”? Many people do.

This plant only really gets noticed in early spring when it is blooming. The bloom is not long lasting, and for such an attention-getting species during the blooming season, the plant is somewhat understated the rest of the year. This doesn’t mean it’s not an attractive plant. As a matter of fact the plant is quite handsome with its dark green, glossy divided leaves and tan to gray, persistent seed pods. Inside the pods are bright-orange to red seeds, somewhat poisonous if you can get past the hard outer shell of the seed. One could swallow the seed and pass it though the digestive tract, both seed and human, unharmed–though I do not suggest experimenting with this.

Texas mountain laurel is slow-growing when first planted. After a few years establishing itself, it can move up to medium-growing if grown in soil that is somewhat prepared, mulched and the plant is getting it’s needs met (which are few). The first many years it will be a shrub. If you slowly, carefully remove some of the lower branches, you can encourage it to be a single or multi-trunked tree. The multi-trunked trees always look nicer than the single-trunked trees, which come off as a bit contrive and forced. Once it becomes a tree, if planted in a place where it can be noticed, it really is a handsome species. Normally it gets to about 10-15 feet high but can reach a height of 30 feet if placed in the proper location.

Plant Texas mountain laurel in full sun. Once it is established it can handle a good, deep watering about once a month. But you must plant the tree/shrub with care (as you should any plant, native or not), making sure a nice layer of mulch protects soil from drying out too fast, and that you are feeding it. We always suggest you feed plants organically, and any organic fertilizer is fine. Some very occasional compost tea, kelp, fish emulsion, etc, is sufficient, and will encourage plants to grow faster.

Texas mountain laurel is native to central Texas, west to New Mexico and south to San Luis Potosi in Mexico. Two related species are sometimes available in the nursery trade, but MUCH rarer:

Sophora arizonica, Arizona mountain laurel is similar but somewhat more diminutive. It is almost always a shrub and the ashy-green foliage is somewhat less lush than Texas mountain laurel though it is still extremely handsome. It will eventually reach about 10 feet tall. It is also totally cold-hardy for Tucson and most of Southern Arizona.

Even harder to find (though much more common throughout the world) is the old world tropics native Sophora tomentosa, or silverbush. The foliage on this shrub is silver and flowers are yellow instead of purple. It grows much faster, to about 10-12 feet tall. There are two varieties available. Sophora tomentosa var. truncata is native to Florida. Sophora tomentosa var. occidentalis is native all over the world on tropical beaches. Surprisingly this species is fairly hardy, though on the coldest of years, when temperatures snap down into the teens F. you might protect it with a sheet. If it suffers some die-back from frost, prune damaged branches in spring.

All species are primarily pest-free, except for infestations by caterpillars of the moth Uresiphita reversalis in late spring. Caterpillar infestations Sophora species have been controlled biologically with a strain of bacteria Bacillus thuringensis, which causes the caterpillars to sicken and die. However I myself let plants succumb to these infestations.

The defoliation caused by the caterpillars is temporary, does not really harm the plants, and the results of these “infestations” are Lepidoptera moths which are beautiful. I always tell people to calm the f**k down and enjoy nature a little instead of rushing to the nursery for eco-war weapons.

For more information on landscaping with native plants, check out Native Plants for Southwestern Landscapes by Judy Mielke.