All but one of the 250 species of annual beard tongue are American natives, although they vary greatly. Virtually all of them are perennial, but some are grown as summer annuals. The name "beard tongue" alludes to the fuzzy, insect-attracting stamens protruding from the open-faced flowers.
Description of beard tongue: P. heterophyllis is a shrub that grows up to 2 feet tall. A native of California, it has many flowers of dark blue, purple, or lilac. The long, narrow flowers are slightly over 1 inch long.
Growing beard tongue: Penstemons will grow in full sun or light shade in hot summer areas, needing slightly acid soil enriched with compost or leaf mold. They grow best in cool, mild winter climates. Set plants 12 to 18 inches apart. In Zones 8, 9, and 10, plants may be started in summer to bloom the next season. Elsewhere, seeds should be sown in mid-winter 12 to 14 weeks before flowering the same season.
Propagating beard tongue: By seeds, cuttings, or division. Seed germination takes 10 to 15 days at a temperature of 55 degrees Fahrenheit. Cuttings or division are often used for choice, named varieties. Cuttings may be taken in the spring and root readily.
Uses for beard tongue: Penstemons can be used at mid-border and are beautiful in mixed plantings or cottage gardens. They can be planted in beds combined with other flowers. Use them at the transition point between garden and woodlands. They make attractive cut flowers.
Beard tongue related species: Penstemon gloxinioides is a name of no botanical standing used for hybrids with large, blousy flowers. Many selections are sold under this incorrect name in a variety of colors, such as scarlet, rose, pink, violet, and deep gentian blue.
Beard tongue related variety: True Blue has deep blue, tubular flowers that contrast nicely with the gray-green leaves.
Scientific name of beard tongue: Penstemon heterophyllis