Santa Fe Botanical Garden

Common name: Rocky Mountain penstemon

Family: Plantaginaceae (Plantain)

Distribution: Southwestern United States, Wyoming

Habitat: Desert scrub, grasslands, pinyon-juniper and oak forests

Hardiness: USDA Zone 3 (-40 to -30 °F)

Life form: Evergreen perennial

Occurrence in New Mexico: New Mexico native plant

Growing Conditions: P. strictus is native to piñon-juniper, scrub oak, ponderosa pine, and aspen communities in northwestern New Mexico, northeastern Arizona, western Colorado, eastern Utah, and southwestern and south-central Wyoming. It is common on plains, meadows, and wooded slopes of our state. This species is commonly included in commercially available wildflower mixtures, and is often seen growing along highways or other areas where it has been seeded. Penstemons need dry, gritty, gravelly or sandy well-drained soils. They are easy to grow in New Mexico and failure is almost always due to excessive moisture after flowering. They grow in soil of low organic content and are short-lived in soil that is too rich. Soil must drain quickly so that the plants’ crowns remain dry. Supplemental water in the first year helps them to become established, but they generally do not need to be watered thereafter. Even during droughts, they should not be watered more than once weekly. In general, penstemons prefer dry soil in winter and some protection from intense winter sun. This penstemon will live 6 or 7 years if deadheaded. A few stems can be left to promote self-seeding.

Description: Rocky Mountain penstemon often grows in large colonies. It grows 1-3 feet tall, with several stems rising above basal foliage. The few stem leaves are paired, lance-shaped, and smaller than the basal leaves. For many weeks in summer, large, showy bluish-purple flowers emerge, mostly wrapped to one side of the stem (a condition termed “secund”). They are 2-lipped with the top bi-lobed lip extending straight out and forming a hood above the 3 deeply cut, reflexed lobes of the lower lip. The anther sacs are widely divergent, with narrow, toothed openings along the distal ends and with long, soft, white hairs. The staminode is usually smooth, but may have a few hairs.