This rare member of the Lamiaceae family, commonly known as big red sage, is a large, erect, hairless (glabrous) perennial herb that grows in specialized habitats such as rocky outcrops, limestone ledges, and moist stream banks. The plant produces stiff, branching stems that can reach impressive heights of up to 5 feet. Its opposite leaves are linear to oblong-lanceolate in shape, measuring up to 5 inches long, and feature margins that range from entire to finely dentate and are edged with tiny hairs (ciliate). These leaves display a distinct structural transition along the plant, being supported by petioles on the lower portions of the stem and becoming completely sessile toward the top.

Throughout a long blooming season that spans spring, summer, and fall, the plant produces numerous showy blossoms arranged in terminal racemes, with 5 flowers clustered at each stem node. The individual bilabiate (two-lipped) flowers grow up to 1½ inches long and display a vibrant reddish-purple to red coloration, featuring an elongated upper lip that extends conspicuously beyond a shorter, two-lobed lower lip. Endemic to the southern Edwards Plateau of Central Texas, big red sage was once feared to be extirpated from the wild, but it has been recently rediscovered in a few isolated native populations within its historic range. Because of its striking appearance and ecological value, it has become available in the commercial nursery and seed trade and has been successfully introduced to cultivated landscapes elsewhere.