Penstemons are beloved for their colorful flowers, but in most areas of the South, they can be problematic to grow. Of the more than 250 species, the majority are native to the West, ranging from Canada to Mexicoand they prefer dry air, cool night temperatures, and excellent drainage, which doesn't sound much like Dixie. Fortunately, there are native Southern species that thrive here naturally; and the hybrids and selections presented here also accept Southern conditions.
Most species have narrow, pointed leaves. Narrow, tubular or bell-shaped flowers are typically 34112 in. long and are held in erect clusters. Bright reds and blues are the common colors, but you'll also find blooms in shades of soft pink through salmon and peach to deep rose, lilac, dark purple, white, and yellow. Blossoms attract hummingbirds. Plants are generally short lived (three to four years). All need fast-draining soil.
P. australis. Zones MS, LS, CS; USDA 7-9. Native from southeastern Virginia to Florida and west to Mississippi. Grows to 3 ft. tall, 112 ft. wide. Creamy white flowers marked with shades of reddish purple bloom in summer.
P. baccharifolius. ROCK PENSTEMON. Zones LS, CS, TS; USDA 8-11. Native to southern Texas. Woody-based growth to 112 ft. high and wide. Small, broad, glossy, dark green leaves with toothed edges have a thick, leathery feel. Coral-pink, inch-long flowers bloom all summer long. Grows on limestone; prefers dry conditions.
P. barbatus. BEARDLIP PENSTEMON. Zones US, MS, LS; USDA 6-8. Native to mountain regions from Colorado and Utah south to Mexico; needs some winter chill for best performance. Open, somewhat sprawling plant to 3 ft. tall, 112 ft. wide. Inch-wide red flowers bloom in tall, loose spikes from midsummer to early fall. Selections include bright pink 'Elfin Pink', with 1-ft. flower spikes; coral-pink 'Rose Elf', with 2-ft. spikes and some rebloom later in fall; and lemon-yellow 'Schooley's Yellow', to 2 ft. tall.
P. canescens. PINK BEARD TONGUE. Zones US, MS, LS; USDA 6-8. Native to dry slopes and woods of the Appalachian Mountains. Green leaves (often densely covered with gray hairs) form a clump 13 ft. high, 1112 ft. wide. Blooms in late spring and early summer, when upright, hairy-gray stems hold pale to dark violet flowers to 112 in. long.
P. cardinalis. CARDINAL PENSTEMON. Zones US, MS, LS, CS; USDA 6-9. Native to New Mexico. Good for borders; takes irrigation well and also tolerates some drought. To 23 ft. tall, 112 2 ft. wide, with thick, dark green leaves. Spikes of brilliant red, 1-in. flowers bloom in summer.
P. cobaea. WILD FOXGLOVE. Zones US, MS, LS, CS; USDA 6-9. Native from Nebraska to Texas. To 12 ft. tall, 1112 ft. wide. Blooms in mid- to late spring, bearing showy clusters of large (2-in.), foxglovelike blossoms in white or lavender with deeper-colored throat markings. Leathery, glossy, green leaves form a basal rosette. Takes little to regular water; tolerates limy soil and clay.
P. digitalis. SMOOTH PENSTEMON. Zones US, MS, LS; USDA 6-8. Native to eastern and central U.S. To 5 ft. tall, 3 ft. wide. Medium green leaves to 7 in. long; flowers to 112 in. long in white or pink shades, often with faint purple lines. Spring to early summer bloom. 'Husker Red', 2123 ft. tall, has maroon leaves and pink- tinted white flowers; 'Pocahontas', 2 ft. tall with lavender-pink flowers; and 'Precious Gem', standing 3 ft. tall with medium pink flowers.
P. dissectus. FEATHERLEAF PENSTEMON. Zones US, MS, LS, CS; USDA 6-9. Native to sandstone outcrops in Georgia's coastal plain. To 2 ft. high, 112 ft. wide. Finely cut leaves; stiff stems topped with inch-long purple flowers in late spring, early summer.
P. havardii. HAVARD PENSTEMON. Zones MS, LS, CS, TS; USDA 7-11. Native to Texas. In spring, several upright, 2- to 4-ft. stems clad in rounded, light green leaves rise from a low foliage rosette to about 2 ft. wide. Scarlet, 2-in.-long flowers bloom from late spring until June. Tolerates a wide range of soils, including limestone and clay. Cut back after bloom.
Cha Cha series. Zones US, MS, LS; USDA 6-8. Bushy plants in a variety of colors grow 20 in. tall and wide. Heavy bloom in summer.
'Dark Towers'. Zones US, MS, LS; USDA 6-8. Compared to P. digitalis 'Husker Red', 'Dark Towers' is bigger and stronger, with pink-purple flowers that create a harmonious combination with the dark foliage. Grows 2-3 ft. tall.
Pensham series. Zones MS, LS, CS; USDA 7-9. Perennial but suitable for use as an annual in zones cooler than recommended. With blooms in late spring and early summer reaching 22 ft. tall, the plant is best in full sun, transitioning to afternoon shade in warmer zones. Although there are many, 'Pensham Laura' is a favorite.
Polaris series. Zones MS, LS, CS; USDA 7-9. Growing 12 ft. tall in full sun to partial shade, the Polaris series blooms in late spring into summer. Colors include Purple, Rose, and Red, all with cheery white throats.
'Prairie Dusk'. Zones US, MS, LS; USDA 6-8. At 12 ft. tall, 'Prairie Dusk' resembles a summer-blooming purple foxglove. Plant it with yellow flowers and foliage to make the purple sing. Full sun.
'Prairie Twilight'. Zones US, MS, LS, CS; USDA 6-9. Hybrid growing 1212 ft. tall with lavender-pink flowers tipped in white. It is a more colorful version of P. smallii. Blooms from late spring into early summer atop burgundy stems and green foliage. Needs well-drained soil. Cut back after bloom.
'Purple Tiger'. Zones MS, LS, CS, TS; USDA 7-11. Large purple bells with white centers on 2-ft. spires.
'Red Riding Hood'. Zones US, MS, LS; USDA 6-8. Growing 22 ft. tall, the red, 1-in. flowers are a long-standing, summer show-off.
Taffy series. Zones US, MS, LS; USDA 6-8. Long-blooming, upright plants that branch at the base. Grows 1824 in. tall and wide. No deadheading needed.
P. multiflorus. WHITE BEARDTONGUE. Zones LS, CS, TS; USDA 8-11. Native to Alabama, Georgia, and Florida, this vigorous species can be quite drought tolerant, although intolerant of wet soil. Normal, well-drained garden soil in partial shade is best. White flowers from spring to early summer. 'Lilac Beauty' has a touch of color.
P. x mexicali. Zones US, MS, LS, CS; USDA 6-9. Summer blooming. Growing 12 ft. tall, 'Red Rocks' has cherry-pink flowers with white throats. The Carillo series, including 'Carillo Red', grow only 810 in. tall with tubular flowers sporting white throats. Both are hummingbird magnets.
P. smallii. SMALL'S PENSTEMON. Zones US, MS, LS; USDA 6-8. Native to North Carolina and Tennessee. Grows 13 ft. tall and 12 ft. wide. Pink-purple or lavender flowers, 1 in. long, in late spring. Tolerates moist woodland soils as well as dry soils.
P. tenuis. GULF COAST PENSTEMON. Zones MS, LS, CS; USDA 7-9. This native of the wet prairies of Louisiana, Texas, and Arkansas blooms heavily in spring, bearing 34-in. pink or purple flowers. To 2 ft. tall and wide, with large medium green leaves. Tolerates wet soils and partially shaded areas. Self-sows to produce plenty of new plants.