Texas mountain laurel (Dermatophyllum secundiflorum, previously known as Sophora secundiflora) is a flowering shrub native to Mexico and the southwestern United States. Not to be confused with Kalmia latifolia, also known as mountain laurel, it's also known as Texas mescal bean (though it's not related in any way to mescal), coral bean, hot bean, frijolillo, and frijolito. In its blooming season it's covered with bunches of brightly-colored flowers of a glorious hue that combines lavender, periwinkle and purple. These flowers also have a luscious scent that some have described as smelling like grape Kool-Aid, similar to the scent of heirloom German irises.
The flower panicles, which resemble wisteria due to their color and shape, appear in early spring, sometimes as early as February, and seed pods follow in summer. Though normally grown as a large shrub, it can also be trained via pruning into a small tree, growing to a maximum height of 20 feet. This shrub is a native evergreen that stays attractive through four seasons, with slender oval leaves that have a smooth, leathery texture. The trunk tends not to grow upright, and the bark is smooth.
Despite not being related to agave, the plant that is the main ingredient for mescal, this plant does have a history of being consumed as a ceremonial hallucinogen by some Native American peoples, who eventually supplanted its use with peyote. The seeds, which dry to a deep red color, have been used to make beads for jewelry. The seeds of this plant are highly toxic, and the flowers and leaves are also toxic to both humans and animals. It is deer resistant and tolerant of difficult growing conditions such as clay soil and drought. It's also loved by pollinators who are drawn to its rich fragrance and colorful blossoms.
|Common Name||Texas mountain laurel, Texas mescalbean, coral bean, hot bean, frigolito|
|Botanical Name||Dermatophyllum secundiflorum|
|Plant Type||Evergreen flowering shrub|
|Mature Size||Up to 20 feet tall|
|Sun Exposure||Full sun to part shade|
|Soil Type||Well drained|
|Soil pH||Slightly alkaline, 5.4 to 6.7|
|Bloom Time||March and April|
|Hardiness Zones||7b to 11, USA|
|Native Areas||Mexico, Southwest US|
|Toxicity||Toxic to people, toxic to pets|
Texas Mountain Laurel Care
Texas mountain laurel is fairly low maintenance once established. It makes a nice patio tree and can also be planted as a hedge. However, it is slow-growing and does take some time to reach mature size. The flower buds form in August for the following spring, so any pruning done late in the season should be done mindfully to avoid snipping off the precious buds.
The Texas mountain laurel is happiest with a fair amount of sun, but will tolerate a partly-shady spot. If planted in a semi-shade area, it prefers afternoon sun.
This shrub is tolerant of a wide range of soils, however it performs best with well-drained soils. Fertilizer is only needed if the soil is very thin of nutrients; overly-rich soils can cause it to grow too fast and become misshapen or form weak branches unable to support the flowers. Adding a bit of calcium to the soil when planting can help the plant get established.
The Texas mountain laurel is quite drought tolerant and good for those who want low-water plants in their gardens. Overwatering can cause too-rapid growth which may cause branch formation to be weak.
Temperature and Humidity
This plant can withstand hot summers and plenty of bright sunlight. It's drought-tolerant but also appreciates adequate rainfall. You shouldn't need to worry about the plant becoming too dry as it does well in an arid or even desert climate. Too much humidity, such as trying to grow in a maritime climate, will decrease the plant's vigor.
Types of Texas Mountain Laurel
There are not many cultivars available for this plant, however some experimenting is bring done with a silver-leafed variety called 'Silver Peso.' This silver variation is said to be slightly more resistant to caterpillar damage. There are also white flowering cultivars available. Check with your nursery supplier to see what cultivars may be available in your region.
Texas mountain laurel benefits from careful pruning in its youth, to assure it grows strong branches and forms a pleasing shape. Once it reaches maturity, pruning only needs to be done to remove damaged branches and maintain the desired shape and height. You can prune into a shrub shape or a small tree, but if you want to train it into a tree shape you should prune carefully in its early years, keeping side growth trimmed and branches well shaped. Because of its slow rate of growth, be careful when pruning to avoid damage to the plant's structure or main branches, which may recover slowly.
This shrub doesn't propagate well from cuttings, due in part to its slow growth rate. The best way to have this plant in your garden is to buy a specimen from a trusted nursery or other supplier. However, those with some time might want to try propagating from seed.
Growing from Seeds
Seeds should be gathered when the pods are still green and the seeds a pale pink color (they later turn red). Soak pods in water if they're difficult to open. Seeds should be scarified before planting; sandpaper is the easiest method for this; scratch the surface lightly until you see tiny nicks. You can plant in containers in potting medium, or direct sow in the garden in the right growing zones. They will take quite a while to germinate. Water daily for two months, then once a week for a year until seedlings appear. Transplant seedlings from containers when they're 3-4 inches tall.
Common Pests and Plant Diseases
Younger shrubs are sometimes bothered by the genista broom moth, which enjoys munching the leaves, but the damage is only cosmetic and will not harm the plant. You can control these pests by using Bacillus thuringiensis; or you can remove them by hand, or with water sprayed with your garden hose. Be aware that over-fertilizing can lead to a caterpillar problem as well, so it's best not to fertilize your Texas mountain laurel.
How fast does Texas mountain laurel grow?
This is a slow-growing shrub and will grow at the rate of roughly two feet per year. It's not advisable to use fertilizers to speed up growth because this can affect the plant's branching and development.
Does Texas mountain laurel bloom in shade?
This shrub does need some sun to bloom, but it will adapt to a partial shade location.
Is Texas mountain laurel toxic?
Yes. All portions of this plant are toxic to humans and animals.