What Is A Texas Mountain Laurel Bush?
Texas mountain laurel (TML) is a hardy evergreen shrub native to the Western United States. It grows from sea level to around 6,000 feet elevation. Its bark is smooth and dark green with light brown spots or stripes along its length. It bears small white flowers in spring and summer followed by berries in fall.
The leaves are opposite, oblong, and up to 1 inch long. They are alternate, broad, and slightly serrate at the tips. Their edges are finely hairy. The leaf blades have five leaflets each with two leaflets per blade. Each leaflet is about 0.5 inches wide and 2 inches long; they are arranged in pairs on either side of the stem near the base of the plant.
The fruit is a berry about the size of a pea. It is oval, round, or elliptical in shape and covered with tiny hairs. The seeds are enclosed within the skin of the seed pod and are surrounded by a thin coating of wax. When ripe, the pods split open revealing their contents inside. The fleshy part of the seed contains only one seed while all other parts contain numerous smaller seeds.
The bark is smooth and dark green with light brown spots or stripes along its length. The stems are smooth and roughly the thickness of a pencil. They grow up to three feet tall and are typically found in clumps.
It flowers from April through July. The greenish white flowers are small, less than 1 inch across. Their scent is distinctive and a little like the smell of a peach. Each flower has four petals that are shaped like a spur that points downward.
The fruit ripens in fall. Each fruit is an oval shape, 1/5 inch long, and contains a single seed. The berries hang in clusters that ripen to a dark bluish-black color. When ripe, the skin of the berries has a thin waxy coating surrounding the hard seed.
More than one species of Texas mountain laurel exist. The most common is the Trans-Pecos Texas mountain laurel, Sophora secundiflora. It grows in clumps and can reach a height of 15 feet. Another species, the Chisos Mountain Texas mountain laurel, Sophora chisosensis, grows at higher elevations.
When and how to prune
The best time to prune your TML is in the springtime. Prune while the plant is still dormant, ideally right after the last frost has passed. Pruning TML during this time of year stimulates new growth and makes the plant better able to withstand the heat of summer.
Pruning your Texas mountain laurel will help it maintain a manageable size and structure while also keeping it from developing disease and pest problems. This is because cutting back on the plant’s size reduces the amount of stress it experiences. It is important to prune your Texas mountain laurel right after flowering because this will give you the best chance of getting flowers the following year.
How and why to propagate
There are several ways that you can propagate your Texas mountain laurel. The easiest and fastest way is by taking stem cuttings in early spring or late summer. Make a sloping cut on the bottom of the stem and remove any leaves below that point. Coat the bottom of the stem with rooting hormone powder then transfer it to a container of water. Place some plastic wrap over the container so that it covers the top but doesn’t touch the water.
This camp creates a mini-greenhouse effect for your cutting and helps to keep the cutting moist. Keep your cutting out of direct sunlight and don’t introduce any more outside air to the container. This will help to maintain the high humidity levels that the cutting needs in order to root.
After several weeks check to see if your stem has roots. If it does you can transplant it into a potting soil and begin treating it like a mature TML. If after three months your stem still does not have any roots you can stop trying to root it, discard it, and start over with a new cutting.
Another way to propagate your Texas mountain laurel is by seed. The seeds require a warm temperature (around 70 degrees Fahrenheit) in order to germinate. Place the seeds on top of moistened seed starting mix and cover with more mix. Keep the soil warm and moist until the seeds begin to sprout, which can take up to several weeks. After they sprout you can transplant them just like other small plants.
If you don’t want to go through the hassle of trying to root a cutting or waiting for seed to sprout you can also propagate your Texas mountain laurel by dividing the larger clumps. This is done in early spring or late fall. Carefully dig up the plant, trying to keep as much of the root system intact as possible, and trim off any dead or dying branches. Replant the new clumps at the same depth that they were originally planted.
Regardless of the method you choose, your newly planted TMLs will require a lot of water and fertilizer in order to get established. Water it at least once a week. After the first year you can begin watering it less frequently but no less than once a month and more in periods of extended drought. Applications of mulch or fertilizer will help keep the roots healthy and encourage new growth. If you can’t get Texas mountain laurel trees you can also use other varieties of laurels such as the Virginia or swamp bay.
These trees prefer a well drained, acidic soil so make sure to add lots of mulch and organic matter. They also prefer a slightly damp soil so if you are in a dry area you may need to water them weekly during the summer. They can get several diseases and insect pests. The most common insect pest is the laurel swollen shoot beetle, which can kill a tree. If this happens it’s best to just remove the tree as controlling the insect is nearly impossible.
Other insects include laurel cherries and laurel leafminers. Diseases include laurel wilt, verticillium wilt, bleeding cankers, and red bay disease.
The Texas mountain laurel is a very hardy tree that grows best in USDA zones 7a-9b. It prefers a well-drained soil with lots of humus and organic matter and an acidic environment around pH 4.5-5.5. It can grow in full sun to partial shade but does best with at least a few hours of sunlight each day.
It doesn’t tolerate drought or salt well so is best suited to areas that have normal rainfall or even places that get saturated by occasional flooding. It also has some issues with root rot in areas that stay soggy for long periods of time.
The flowers of the Texas mountain laurel are small and greenish but it’s best known for its shiny, leathery, deep green leaves. These leaves can grow up to three inches wide and have a shiny surface that makes them distinct from other types of laurels. The leaves are deeply lobed, usually 7 but sometimes 5 or 9. Each leaf is made up of between 2 and 5 pairs of leaflets with each pair having a small, spine-like projection in the center. The margins have small, sharp teeth.
The fruit of the laurel is similar to an orange cherry but still on the stem and soft when it’s young. As it matures it turns red or purple then yellow then brown as its seed is released. It grows in clusters that ripen over a period of several weeks in the fall.
The Texas mountain laurel is also known as the southwest or Mexican laurel. It is native to the Southwestern United States and Mexico, growing from Arizona and New Mexico south to Nicaragua. It can be found at moderate to high elevations in forests or on rocky hillsides. It prefers neutral to slightly acidic soil and can handle quite a bit of shade. It is drought tolerant and will often survive long dry spells with no water.
The wood is very hard and heavy, weighing more than twice that of red oak, so it is rarely used. Native Americans chewed the roots for sap but they are not edible in any quantity. Today it is occasionally used for ornamental woodworking and in some craft projects.
The Latin name comes from two words: “integumentum” meaning a cover or a lid and “oleum” meaning oil. This refers to the belief that Texas mountain laurel contains a deadly poison called oleandrin in the roots and bark, which was used to make poison arrows by Native Americans.
The oleander family is commonly grown in warmer areas as an ornamental due to its pretty flowers. It is highly toxic though, causing severe diarrhea, vomiting, dizziness, slowed heart rate, drowsiness and even death. Every part of it is poisonous and it takes very little to cause a serious reaction. The toxin affects the heart so can be fatal if enough is ingested. Many animals are instinctively wary of it but it often grows freely around the house and is still a common plant for children to mistake for an edible fruit.
Sources & references used in this article:
Mycorrhizae, survival and growth of selected woody plant species in lignite overburden in Texas by FT Davies Jr, CA Call – Agriculture, ecosystems & environment, 1990 – Elsevier
Response of Sophora secundiflora to nitrogen form and rate by EF Gilman, DG Watson – Florida Cooperative Extension Service, Fact Sheet ST …, 1994
A study in horticultural therapy: Matt’s seed story by G Niu, D Rodriguez, M Gu – HortScience, 2011 – journals.ashs.org
Pruning Shrubs in the Low and Mid-Elevation Deserts in Arizona by H Shoulders, A Wray – HortTechnology, 1995 – journals.ashs.org
Mescalbean (Sophora secundiflora) Poisonous for Livestock. by UK Schuch – 2016 – repository.arizona.edu
Kalmia latifolia L. by IB Boughton, WT Hardy – Texas FARMER Collection, 1935 – oaktrust.library.tamu.edu
Improving competitive status of oak regeneration using stand management and prescribed fires by FA Blazich, MC Starrett – Citeseer
White-tailed deer browse preferences for South Texas and the Edwards Plateau by JS Ward – Journal of Sustainable Forestry, 2015 – Taylor & Francis