Penstemon tenuis, also known as Brazos Penstemon, Brazos Beardtongue, Sharpsepal Beardtongue, Gulf Penstemon, and Gulf Beardtongue, is a plant species native to southeastern and East Texas. It has tapering leaves, usually 3-6 inches long and medium green in color. In North Texas, it is generally evergreen, with foliage that can be up to 12 inches wide and 12 inches tall. When it produces flower spikes in the spring, its height can reach up to 30 inches.

The plant produces large numbers of light purple flowers in mid- to late spring on multiple flower spikes, giving the appearance of a cloud of blooms that last for several weeks. Sometimes, it produces flowers again in the fall, but the blooms are more limited. After flowering, the plant has attractive, rugged 0.5-inch seed capsules containing many tiny seeds that stay on the plant through the winter unless cut off.

Gulf Coast Penstemon is mainly grown for its showy, lavender-purple flowers. During blooming, it serves as a nectar source for bees, insects, and butterflies and attracts hummingbirds. The plant's flowers are relatively long-lasting in bouquets, making it suitable for a cutting garden. It self-seeds prolifically, and plants can form a thick mat that can serve as ground cover over time. To avoid prolific seeding, cut the flower stalks after blooming. This practice may also promote a further round of blooming.