Unique and rare native plants add excitement to Valley nature parks
by Anita Westervelt, Texas Master Naturalist

Extreme south Texas’ native habitat has some pretty unique plants that are not found elsewhere in the U.S.

Mexican buttonbush, Cephalanthus salicifolius, is one such shrub that only grows on the banks of the Rio Grande in Cameron and Hidalgo counties. Its native range extends south through much of the middle of Mexico. A separate population of the plant exists in Honduras.

Although native, it is considered rare in Deep South Texas. The good news, a number of nature centers, with the right conditions, are beginning to discover the benefits of adding Mexican buttonbush to their habitats, especially in butterfly gardens.

Its unusual flowers are the real show and a plant photographer’s dream. The flowers form one inch in diameter globes. The corollas, the petals of the flowers, are white and densely cover the globe. The white stamen extend beyond the flowers and are topped by an oval-shaped, golden anther that appears to glow in the sunlight.

Mexican buttonbush is an excellent nectar source, attracting many different kinds of butterflies and other insects that draw nectar.

As the flowers mature from bud to fruit, the plant offers a great photographic study, spring through winter, for anyone with any type of camera.

Mexican buttonbush has a high tolerance to heat, blooms spring through summer in partial to full sun. Its preferred habitat is wet areas along river banks, wetlands, marshes and muddy soils.

Also called willow leaf buttonbush, the leaves are narrow, shiny, oblong blades nearly five inches long that drop off during winter. Older branches turn a reddish brown.

The shrub can grow from eight to 18 feet tall and spread four to 10 feet.

After the flowers mature, they turn into hard ball-like fruits consisting of multiple small two-seeded nutlets.

Mexican buttonbush is closely-related to common buttonbush, Cephalanthus occidentalis, which grows throughout Texas and all but 11 mostly northwestern American states. The leaves of common buttonbush are longer, wider and oval in shape.

Anytime our rare native plants become popular and residents begin to plant them in home gardens, it helps to ensure posterity of our native habitat.

Texas Master Naturalist volunteers are active in transplanting and establishing threatened and rare species in local parks and nature preserves whenever possible and help collect seeds for local native plant growers.

For a list of nurseries selling native plants, please visit the Rio Grande Valley Chapter, Texas Master Naturalist Website at www.rgvctmn.org.

The Rio Grande Valley Chapter, Texas Master Naturalist
develops knowledgeable volunteers dedicated to the study and conservation of
natural resources and natural areas in the Lower Rio Grande Valley and helps
the natural world through service, outreach and education.