Tepeguaje tree: A great leader for a native habitat

What could be more perfect than a rapid growing, thornless, shade tree with fragrant flowers and feathery leaves on wispy branches that waft and dance in gentle summer breezes? Did I mention the beautiful, shapely canopy?

Tepeguaje, Leucaena pulverulenta, also called great leadtree and Mexican leadtree, is native to Mexico and grows in the Rio Grande Valley and south to Chiapas in southern Mexico. It is a leguminous tree in the pea family that can reach heights of 30 to 55 feet.

Tepeguaje leaflets (Courtesy: Anita Westervelt)

The tree blooms in spring and summer and after rain. Flowers grow in clusters, beginning as tiny soft green, spiky orbs, maturing into creamy white round puffy balls about three-quarters of an inch across and followed by dark brown, long, flat, papery legume pods that contain numerous seeds.

A drawback to this near-perfect tree is that although it is heat tolerant, it is cold-sensitive and not reliable north of its native Texas range. The wood is hard, but the branches are brittle.

Back to its good points: its lofty canopy provides nesting and resting sites for wildlife and the flowers draw nectar insects, which in turn bring birds. Tepeguaje is an important species in restoration efforts. Being a legume, it is a nitrogen fixing tree, providing an important natural ecological process. Its broad canopy provides shelter for various seedlings as they mature. Tepeguaje is short-lived, allowing the other longer-lived native species to replace it, thereby creating a productive and self-sustaining ecological system.

But beware. There’s an imposter. Tepeguaje is easily confused with noxious Popinac, Leucaena leucocephala, that can be found from Houston and San Antonio to the Rio Grande Valley. Native to tropical America, Popinac was introduced in Florida and Texas as high protein cattle fodder, and for land reclamation and erosion control. It reproduces prolifically. Clumps of five to 20 seed pods per flower head develop, each pod containing from eight to 18 seeds, according to a Texas Invasive Species Institute online data sheet.

Popinac can form dense monospecific thickets by altering the soil to the point where it can prohibit the growth of native plants, a condition that may be difficult to reverse even when the invasive trees are eradicated.

To distinguish the two trees, you cannot rely on the buds and blooms, as they are nearly identical; check the leaf structure. Native tepeguaje has narrow leaflets that have little or no space between them. Popinac has broader leaflets with noticeable spaces between the leaflets.

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Invasive Popinac flowers and leaflets (Courtesy: Anita Westervelt)

Tepeguaje buds and blooms (Courtesy: Anita Westervelt)

Invasive Popinac seed pods (Courtesy: Anita Westervelt)

Tepeguaje legumes (Courtesy: Anita Westervelt)

Tepeguaje tree at South Texas Ecogtourism Center (Courtesy: Anita Westervelt)

Tepeguaje leaflets (Courtesy: Anita Westervelt)

See the real deal on your next beach trip. Stop at South Texas Ecotourism Center on Texas Highway 100, at Laguna Vista, for a look at a tepeguaje tree less than three years old. For more information about the ecotourism center, visit https://stec-lv.org/.

November through February traditionally are tree planting months in the Rio Grande Valley. Native trees are encouraged in order to help protect the native habitat. Link to a list of local native plant growers: https://www.stbctmn.org/post/valley-native-plant-growers-nurseries

Interested in becoming a Texas Master Naturalist? Register for the 2025 classes here: https://www.stbctmn.org/the-next-class.

Other sources helpful in writing this article were: NativePlantProject.com; wildflower.org; aggie-hort.tamu.edu; plantanswers.com/native; and Richardson, A., King, K. 2011. “Plants of Deep South Texas: A Field Guide to the Woody and Flowering Species.” Texas A&M University Press, College Station.

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