penstemon

Penstemon, commonly known as beardtongue, is a genus of flowering plants in the family Plantaginaceae. The genus comprises numerous species native to temperate regions of North America, with a concentration in the western United States; a smaller number occur in Central America. They are primarily herbaceous perennials, and some species form woody subshrubs.

Morphology centers on erect stems with opposite, simple leaves. The flowers are tubular and bilabiate, with five lobes, and are usually arranged in terminal panicles or racemes. Colors span blue, purple, pink, red, and white, and the tubular blossoms are adapted for pollination by bees and hummingbirds. A distinctive feature in many Penstemon species is a conspicuous hairy sterile stamen, or staminode, inside the corolla that gives rise to the common name beardtongue.

Taxonomy and name: Penstemon is placed in Plantaginaceae as a result of modern classifications; it was formerly placed in Scrophulariaceae. The genus name derives from Greek roots meaning “five stamens,” referencing the flower’s stamens, often with one sterile stamen (staminode) that appears bearded.

Ecology and cultivation: Penstemon species are adapted to a variety of habitats, including meadows, open woodlands, sagebrush flats, and rocky slopes. They are generally drought-tolerant once established and prefer full sun with well-drained soil. In cultivation, they are valued for their long bloom period and attract pollinators. Propagation is by seed or cuttings; some cultivars are selected for compact growth or distinctive flower color. They can be susceptible to crown rot in poorly drained soils and may be affected by slugs or snails in garden settings.