The Texas Mountain Laurel (Dermatophyllum secundiflorum), also known as the mescal bean, is a beautiful evergreen shrub or small tree that is native to central Texas, west to New Mexico, and south to central Mexico. It grows 10 to 15 feet tall with a canopy spread of 8 to 10 feet. It’s a slow grower and typically maintains a strong shrub growth habit, rarely taking on tree form in nature. In cultivation it can be trained as a multi-trunked small tree or kept as a shrub.
Texas mountain laurel is a completely different species and in a different genus from mountain laurel. Almost everything about this Southwest native is very different from the eastern mountain laurel, including its size, shape and flower color.
The Texas Mountain Laurel has glossy, dark green compound leaves that are composed of leathery leaflets. The leaves stay on the tree year-round. It also has purple, wisteria-like flowers that bloom in the spring. The aroma from these blooms is quite pleasant and is very similar to the smell of the artificial grape flavoring found in drinks and gums.
After the flowers fade, the Texas Mountain Laurel produces brown, leathery seed pods. The seed pods contain bright red seeds that are poisonous if ingested. However, the seeds are hard and difficult to crack, so poisoning is not a common problem.
Historically, the Texas Mountain Laurel has been used by Native American tribes for various purposes. The Mescalero Apache, for example, used the seeds of the Texas Mountain Laurel, along with other ingredients, to create a potent hallucinogenic drink. The seeds were also used in jewelry and for trade.
In terms of its botanical history, the Texas Mountain Laurel was first described by Spanish botanist José Antonio Pavón y Jiménez in the late 18th century and classified as Sophora secundiflora. It was later transferred to the genus Dermatophyllum by American botanist Asa Gray in the mid-19th century. Recently Texas Mountain Laurel’s scientific name was recently changed to Dermatophyllum secundiflorum by [University of Arizona Campus Arboretum].
The Texas Mountain Laurel is a relatively low-maintenance plant that is drought-tolerant once established. It prefers well-drained soil and full sun. With proper care, the Texas Mountain Laurel can be a beautiful and long-lasting addition to your landscape. Tt’s hardy in U.S. Department of Agriculture plant hardiness zones 8 through 11.
How to Grow and Care for Texas Mountain Laurel
- Choosing the Right Location: This tree thrives in full sun to partial shade. Choose a location that receives at least 6 hours of direct sunlight daily. This plant is also tolerant of a wide range of soil types, from sandy to rocky, but it prefers well-drained soil.
- Planting: Plant the tree in the spring or fall when the weather is mild. Dig a hole that is twice as wide and just as deep as the root ball. Gently loosen the roots and place the plant in the hole, ensuring that the top of the root ball is level with the ground. Backfill the hole with soil, tamping it down gently to eliminate air pockets. Water thoroughly after planting.
- Watering: While this tree is drought-tolerant once established, it will need regular watering for the first year to help it establish a strong root system. Water deeply once a week during the first year, allowing the soil to dry out slightly between waterings. After the first year, you can reduce watering to once every two weeks or less, depending on your local climate conditions.
- Fertilizing: This tree does not require a lot of fertilizer. In fact, over-fertilizing can lead to weak growth and an increased susceptibility to pests and diseases. If you choose to fertilize, use a slow-release, balanced fertilizer in the spring.
- Pruning: Prune the tree in the spring, after it has finished blooming. Remove any dead, diseased, or damaged branches, and shape the plant as desired. Avoid pruning too heavily, as this can reduce flowering the following year.
- Pests and Diseases: This tree is generally pest-free, but it can be susceptible to scale insects and spider mites. Monitor your plant regularly and treat any infestations promptly with an appropriate insecticide or miticide.
- Propagation: The tree can be propagated from seed or semi-ripe cuttings. Seeds should be soaked in water for 24 hours before sowing in well-draining soil. Cuttings should be taken in the summer and rooted in a well-draining rooting medium.
Planting from Seeds
- Seed Collection: Gather seeds when the pods turn greenish-gray/pinkish, before the red shell hardens. Seeds with a pink tint or red blotch germinate well.
- Scarification: Seeds benefit from scarification, which weakens the tough outer coat and aids germination. You can nick them with sandpaper or a file until the light-colored inner coat shows.
- Planting: Plant seeds in spring when soil warms, or in fall if using fresh, swollen seeds from the pod. Sow them ½ inch deep in well-drained potting mix or directly in the garden (in suitable zones). Germination can be slow, so be patient.
- Seedling Care: Water daily for the first two months, then reduce to once a week for a year. Transplant seedlings to containers when they reach 3-4 inches tall. Protect young container plants from freezing temperatures during the first winter.
How to Prune
Perform maintenance pruning when the bush is dormant, either in winter or in summer’s heat. Flower buds develop on the ends of branches during August, remaining dormant through the winter. Pruning after August decreases the spring bloom. Perform light hedge pruning in April or May. As plants get larger after 15 years, decide if you want to allow them to grow to their full height or if you want to keep them shorter to promote bushiness and to keep blooms closer for better viewing.
When plants are young, don’t prune them at all. Texas mountain laurel grows slowly during the first five to 10 years of life. Allow the plants to attain some size before shaping them. Don’t remove more than one-third of the growth at a time. First remove dead or damaged branches. Then look for branches with spindly growth, narrow crotches or crossing branches. Take branches back to the point where they join the next larger stem. You don’t need to use pruning paint. Prune hedge plants minimally, lightly heading back individual branches to keep plants to desired size.
To develop small trees, choose one to three main branches as the main trunks and remove the lower branches from them. Cut away any smaller trunks at ground level. Watch for and remove any suckers as the plant continues growing. As the tree grows, you can gradually raise the canopy height by removing other lower branches. Use caution because these older plants are valuable specimens and might not recover from overpruning. Tree-like stature is usually attained after 20 years or more. Really old specimens can reach 50 feet tall.
Varieties of Texas Mountain Laurel
The Texas Mountain Laurel (Dermatophyllum secundiflorum) is a single species within the genus Dermatophyllum. However, there are several cultivars of Texas Mountain Laurel that have been developed for their unique characteristics.
- Alba: This cultivar produces white flowers instead of the usual purple.
- Silver Peso: This cultivar has a silvery sheen to its leaves, giving it a unique appearance.
- Silver Cloud: Similar to Silver Peso, this cultivar also has silvery leaves.
- Lena: This is a dwarf cultivar that grows to only about 3 feet tall, making it a great choice for smaller gardens or container growing.
Common Problems Texas Mountain Laurel
- Leaf Spot: One of the most common issues with Texas Mountain Laurel is leaf spot, which is caused by various fungal pathogens. This disease is recognizable by the presence of dark spots on the leaves.
- Canker: Canker causes sunken, dead areas on the branches and can lead to the death of the affected branch.
- Genista Caterpillar: The Genista caterpillar is a common pest that feeds on the foliage of Texas Mountain Laurel. It forms loose webbing on the leaves and can cause significant defoliation if not controlled.
- Scale Insects: Scale insects can infest Texas Mountain Laurel, sucking sap from the plant and causing damage.
- Root Rot: Texas Mountain Laurel can be susceptible to root rot, especially in poorly drained soils.
- Sunburn: Texas Mountain Laurel prefers partial shade to full sun. In full sun, especially during the hottest part of the day, the leaves can get sunburned, causing them to turn yellow or brown.