Texas Native Plant Month

– Tip your hat to the ancient guayacán

Guayacán, Guaiacum angustifolium, in full bloom. (Photo by Anita Westervelt)

Published April 18, 2026, in the McAllen Monitor

Story and photos by Anita Westervelt

Guayacán, Guaiacum angustifolium, is one of the more beautiful native trees in the Rio Grande Valley. It is a gnarled, multi-trunked, slow-growing, number one browse pick for white-tailed deer in the wilds of the Texas-Tamaulipan thorn scrub.

If that sounds like something you would rather avoid, note that it is one of the more spectacular treats you can expect from our native habitat when it is in full bloom in our local nature parks. Guayacán trees bloom in spring and after a rain – both conditions currently being met.

The tree grows about an inch a year, eventually reaching heights of eight to 15 feet, its crooked limbs defining its own unique shape. It can be interesting in all seasons. Its short, thick, feathery dark green leaves grow close to the knotty gray branch stems and stay green all year. The leaves fold inward during the heat of the day and night to conserve water.

Small, fragrant, orchid-like flowers have reddish lavender to dark purple petals that surround a crown of pale green stamen and artfully contrasting golden anthers. In bloom, the tree can be teeming with butterflies and bees. Hummingbirds visit the flowers.

A Guayacán flower and developing green fruit. (Photo by Anita Westervelt)

The blooms turn into unique, heart-shaped green pods that ripen to yellow, orange or a rich cinnamon color in autumn. When the capsule dries, it splits open, revealing one to three seeds nearly the size of pinto beans, which are covered in a bright red fleshy coating called an aril. Birds and small mammals eat the fleshy part and help disperse the hard inner seed.

A ripe seed pod splits open. (Photo by Anita Westervelt)

A seed pod may have one to three aril covered seeds. (Photo by Anita Westervelt)

The tree is a host plant for the lyside sulphur butterfly, little yellowish-green butterflies whose northern range is the Rio Grande Valley. It also hosts gray hairstreak and marine blue butterflies and certain owlet and geometer moths. At night, the flowers are a significant nectar source for adult moths.

In the wild, guayacán often grows in colonies. Its range is primarily on the dry, poor soils of south and the west Texas Tans-Pecos region and into northern Mexico. It is commonly known for its deep tap root which allows for its extreme drought and high heat tolerance.

Guayacán provides critical forage; the leaves are highly nutritious, containing 14 to 26 percent crude protein, making it a first choice browse plant for white-tailed deer in south Texas, according to a Texas A&M AgriLife Extension online paper. Guayacán is also consumed by livestock, rabbits, and rodents. The dense crooked structure of guayacán provides excellent nesting for birds and cover for wildlife.

Although not rare in old growth forests, guayacán is not commercially readily available. Propagation is difficult and generally by seed. A tree may take 20 years to reach maturity and possibly five years before it will produce blooms. They can live for centuries. Local native plant growers may collect guayacán seeds and offer plants for sale. A contact list is at this link: https://www.stbctmn.org/post/valley-native-plant-growers-nurseries.

To view mature trees, contact your favorite local nature parks. Nature preserves in Hidalgo County that showcase mature guayacán trees include Frontera Audubon Society, Santa Ana National Wildlife Refuge, Estero Llano Grande State Park, Bentsen-Rio Grande Valley State Park and the National Butterfly Center.

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