Penstemon tenuis

gulf coast penstemon, sharpsepal beardtongue, brazos penstemon, brazos beardtongue, gulf penstemon, gulf beardtongue, gulf coast penstemon, gulf coast beardtongue, sharp-sepal penstemon, sharp-sepal beardtongue


Leaf Arrangement


Leaf Attachment


Leaf Type

cauline, simple

Leaf Shape

oblong, lanceolate

Growth Form


Flower Color

blue, pink, purple

Flower Month

March - June

Height (meters)

0.4 - 0.9

Milky Sap








Growing Season

Cool season

Wetland Class


Prairie Coefficient of Conservatism


Cultural Information

Beardtongue prefers full to a half day of full sun and a light and well drained, sandy, or gravelly soil. It rots easily in wet places or places with excessive organic matter. Beardtongue blooms for 2-4 weeks. Related species are Penstemon smallii, P. canescens, and P. laxiflorus. Seeds are tiny and dark brown or black at maturity. To harvest seeds cut the stalk and place into a paper bag upside down. Store the bag in a cool, dry place until the seeds dry and fall from the pods. Shake the bag to remove all the seeds then screen to clean. If the pods are not ripe enough it may be necessary to crush the capsules screen them. Seed should be sown fresh or moist stratified after storage at 33-40 F for 30 days (Philips 1985, Shirley 1994). Penstemons reseed readily in loose soil and the plantlets thus produced may be transplant. There are 3,300,000 seeds/lb and the recommended seeding rate is 1 lb/acre (USDA 1948). Clumps may be divided in fall or early spring.

Natural History

This species is mostly restricted to the gulf prairies and marshes in Louisiana and Texas and is sometimes also found in Arkansas. It occurs mostly in poorly drained loam to clay soils. This species has great merit as a perennial along the humid gulf coast. A variety of Penstemon tenuis now in cultivation is called "gulf coast" Penstemon.


Unpoorly drained loamy soils.