SPECIES FOR AREAS WITH HOT, DRY SUMMERS AND COLD WINTERS
BRIGHTLY COLORED FLOWERS
This group includes flashy species that insist on dry conditions and hot summers. They are cold-hardy to at least Sunset climate zone 2b (from the Sunset Western Garden Book). They are not long-lived, lasting from three to five years. The brightly colored species are favored by hummingbirds. Bloom is midseason (late spring and early summer), unless noted.
Penstemon barbatus. Red orange flowers. 3 to 5 feet tall. Good cut flower. Selections include compact 'Elfin Pink' (18 inches) and 'Schooley's Yellow'.
P. cardinalis. Burgundy. 2 feet.
P. clutei. Rose pink. 3 feet. Nice waxy blue gray foliage.
P. eatonii. Red orange; early. 3 feet.
P. floridus. Bright pink. 3 to 4 feet.
P. grandiflorus. Very large flowers in lavender, pink, or white. 2 to 3 feet. Blue gray foliage shaped like florists' eucalyptus. Good selections are Prairie Jewel (same colors as species), 'Prairie Snow' (white), War Axe (deep pink and purple).
P. palmeri. Very large pale pink flowers. 3 to 6 feet. Blue foliage.
P. pseudospectabilis. Magenta. 2 to 4 feet.
P. rostriflorus. Red orange; late. 2 to 3 feet. Somewhat shrubby.
P. utahensis. Coral red. 1 to 2 feet.
P. virgatus. Lavender. 2 feet.
Some of the best true-blue blossoms in the plant kingdom are found in this group. All are hardy to zone 2b, most even to zone 1. They prefer dry soil, cool nights, and low humidity. They bloom for several weeks at midseason.
P. cyananthus (Wasatch penstemon). Bright medium blue. 18 to 24 inches. Hardy to zone 1.
P. glaber. Large, bright medium blue flowers. 18 to 30 inches. Hardy to zone 1.
P. mensarum (Grand Mesa penstemon). Cobalt blue. 15 to 20 inches. Hardy to zone 2a.
P. neomexicanus (New Mexico penstemon). Indigo blue. 2 feet.
P. speciosus. Bright medium blue. 15 to 30 inches.
P. strictus (Rocky Mountain penstemon). Indigo blue. 2 feet. Hardy to zone 1.
P. virens (blue mist penstemon). Sky blue. 10 to 15 inches tall. Hardy to zone 1. Tolerates a bit more moisture and light shade than others.
SPECIES FOR HOT, DRY AREAS WITH MILD WINTERS
This group includes some of the tallest species, all native to southern Arizona, California, and Mexico. Their thick, waxy foliage adds to their appeal. They need heat to perform well and are not winter-hardy in the intermountain region. Their life span is typically three to five years. Most are favored by hummingbirds.
P. centranthifolius. Red; early to midseason. 4 to 5 feet. Long bloom season.
P. clevelandii. Rose pink; early. 2 to 3 feet.
P. parryi. Rose pink; early. 3 to 4 feet.
P. spectabilis. Indigo blue; early. 4 to 5 feet.
P. superbus. Red; early. 5 to 6 feet.
These species grow less than 1 foot tall and are hardy to at least zone 2b. They have attractive evergreen foliage and mounding or mat-forming habits. All bloom midseason, unless noted.
P. californicus. Deep purple. Silver foliage. Needs hot, dry conditions.
P. crandallii. Medium blue. Needs dry conditions. Prefers cool climates.
P. davidsonii davidsonii. Purple. Prefers cool climates. Protect from winter wind.
P. hirsutus 'Pygmaeus'. Pale lavender. Tolerates light shade.
P. linarioides coloradoensis. Lavender blue. Gray foliage. Needs dry conditions.
P. pinifolius (pineleaf penstemon). Red, orange, or yellow. Long blooming.
P. procerus tolmiei. Blue, lavender, pink, or yellow.
P. procumbens (P. caespitosus). Blue; early. Needs dry conditions.
P. rupicola. Rose red. Prefers cool climates. Protect from winter wind.
P. teucrioides. Light blue. Needs dry conditions.
COLORFUL HYBRIDS FOR COASTAL AREAS
Sometimes referred to as garden penstemon or European hybrids, these showy plants were once bred mainly overseas. Best suited to coastal areas, they dislike intense heat and are not reliably cold-hardy in the interior West. As a group they are short-lived, but the darker-flowered selections tend to grow longer. They need regular water during the growing season and autumn. Typically, they grow 18 to 30 inches tall and bloom late.
Bright reds. 'Firebird', 'Flame', 'Razzle Dazzle', 'Red Ace', and 'Scarlet Queen'.
Dark reds. 'Blackbird', 'Burgundy', 'Garnet', and 'Port Wine'.
Pink and rose. 'Evelyn' (one of the hardiest), 'Hidcote Pink', 'Lynette', 'Patio Pink', 'Pennington Gem', 'Pink Endurance', and 'Wisley Pink'.
Purple. 'Hidcote Purple', 'Midnight' ('Russian River'), 'Papal Purple', 'Purple Tiger', and 'Raven'.
Blue or lavender. 'Alice Hindley', 'Knightwick', 'Sour Grapes', and 'Stapleford Gem'.
Color blends. 'Astley' (white-pale lavender), 'Mother of Pearl' (white-lavender), and 'Raspberry Flair' (lavender-rose).