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Penstemon

Beard Tongue
Scrophulariaceae
Perennials

There are some 250 species of penstemon. Most are native to the West, ranging from Canada into Mexico; some grow on the highest mountains, some in the desert, and others in forest glades, in foothills, on plains. A few are widely available, but most are sold only by specialists. Some of the perennials described here have woody-based stems, while others are herbaceous. Most species have narrowish, pointed leaves; those in basal foliage clump are larger, those on flower stems are smaller. Narrowly bell-shaped, lipped flowers (usually 3/4–1 1/2 in. long) are most commonly seen in bright reds and blues, but they also come in shades from soft pink through salmon and peach to deep rose, lilac, dark purple, white, and, rarely, yellow. Blossoms of some species attract hummingbirds.

Need fast drainage. Species in particular benefit from rock garden conditions. Usually short lived (3 or 4 years). Hybrids and selections tend to be easier to grow than wild species alongside regular garden plants; wild kinds may die quickly if given too-rich soil and too much water. In dry years or with restricted water, however, plants of wild species may thrive.

Penstemon barbatus

Needs some winter chill for best performance. Native to mountain regions from Colorado and Utah south to Mexico. Open, somewhat sprawling habit to 3 ft. or higher and 1 1/2 ft. wide. Bright green foliage. Long, loose spikes of red flowers over a long period, starting in late spring or midsummer. One of the best penstemons for humid-summer areas. Look for foot-tall hybrid ‘Elfin Pink’, with clear pink flowers; 2 1/2-ft. hybrid ‘Rose Elf’, with deep rose blooms; and 2-ft. variety ‘Schooley’s Yellow’, with soft lemon yellow flowers.

Penstemon cardinalis

Native to southern New Mexico and Texas. Leafy habit to 2 1/2 ft. tall and 2 ft. wide. Large, leathery, dark green foliage. Dark red flowers bloom all summer; very popular with hummingbirds. Long-lived, adaptable plant that thrives even in areas with humid summers.

Penstemon centranthifolius

Native to Coast Ranges of California. Grows to 2– 3 ft. tall and 1 1/2–2 ft. wide, with waxy gray leaves that vary from lance shaped to oval. Long spikes of narrow bright red flowers in spring or early summer.

Penstemon digitalis
Penstemon digitalis

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Penstemon digitalis

Native to the eastern and central U.S. grows to 3–5 ft. tall and 2–3 ft. wide, with long, medium green leaves and clusters of white or pale pink flowers in summer. Tolerates heat and humidity. Popular ‘Husker Red’ grows to 2 1/2–3 ft. tall and has maroon foliage and pinkish white flowers.

Penstemon eatonii

Native to the mountains of the desert Southwest. This scarlet-flowered species is similar to P. centranthifolius. Grows to 1–3 ft. tall and wide and has lance-shaped, leathery green leaves, sometimes with a whitish bloom (but without a waxy coating). Flowers appear on tall spikes in spring to early summer. Tolerates heat.

Penstemon heterophyllus purdyi
Penstemon heterophyllus purdyi

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Penstemon heterophyllus

California native of variable appearance, with glossy bluish green foliage and crowded spikes of narrow blossoms ranging from reddish purple to deep blue. Usually grows to 1 1/2–2 ft. high and 2–3 ft. wide. Blooms in spring and early summer. 

Dependable and long-blooming ‘Margarita BOP’ grows to 1 1/2–2 ft. high and 2–3 ft. wide, with sky blue flowers that fade to purple. P. h. purdyi has darker green foliage than the species and rosy lavender to intense blue flowers.

Penstemon hybrid
Penstemon hybrid

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Penstemon hybrids

Perennials in Zones 6–9, 14–24; treated as annuals elsewhere (grow as a winter annual in Zones 12, 13). All are compact, bushy, upright plants to 2–4 ft. tall and 3 ft. wide, with narrow green leaves. Large (to 2-in.) summer flowers in loose spikes at stem ends, in almost all colors but blue and yellow. Mass these plants in borders or group with other summer-flowering plants. Where grown as perennials, set out nursery transplants in fall for bloom in late spring and early summer. After the flowers fade, cut back to side growth for another round of bloom in late summer, early fall. This group of penstemons prefers regular water but is subject to root rot in wet, heavy soils.

‘Alice Hindley’: Shiny foliage and pale lilac blooms with white throats.

‘Apple Blossom’: Pink flowers with white throats.

‘Blackbird’: Dark maroon blooms held on deep red stems.

‘Evelyn’: Soft rosy pink blooms on a fine-leafed, bushy plant.

‘Firebird’ (‘Schoenholzeri’): Scarlet flowers on a vigorous, heavy-blooming plant.

‘Garnet’ (‘Andenken an Friedrich Hahn’): Fine-leafed plant with wine red blooms. Long-lived and floriferous.

‘Hidcote Pink’: Heavy producer of coral pink flowers with a white, maroon-streaked throat.

Kissed series: These large-flowered selections have white-throated blooms with lips in bright colors: ‘Cerise Kissed’, ‘Coral Kissed’, ‘Violet Kissed’, ‘Wine Kissed’.

‘Midnight’: Vigorous, bushy plant with deep green leaves and dark bluish purple blooms.

‘Sour Grapes’: The true variety has flowers in a combination of violet and metallic blue, but some plants sold under this name may have bright red-violet blooms. 

Penstemon mensarum

Native to western Colorado. Herbaceous stems to 2–3 ft. high and 1–1 1/2 ft. wide. Dark green basal foliage. In spring, the plant bears the most fiercely brilliant dark blue flowers of the cultivated penstemons. Excellent performer in mountain regions. Tolerates considerable shade and thrives with moderate watering.

Penstemon Mexicali hybrids

Bushy growth to 1 1/2 ft. high and wide, with profuse, narrow, shiny green leaves. Blossoms of ‘Pike’s Peak Purple’ are violet, those of ‘Red Rocks’ bright rose. Burgundy and pink forms are also available. Highly recommended for Rocky Mountain and Great Plains states; they rival the border penstemons for showiness of leaf and flower, yet are much hardier to cold. Bloom all summer. Do well with moderate water but tolerate regular moisture.

Penstemon palmeri

Native to the mountains of the desert Southwest. Grows to 4–6 ft. tall and 2–3 ft. wide, with thick, grayish blue leaves. This is among the few scented penstemons, with flower stalks bearing fragrant light pink blossoms in early summer. Will bloom the first year from seed. Thrives in hot, dry conditions. Sandy or gravelly soil is essential.

Penstemon parryi

Native from Arizona into Mexico. Grows to 2–4 ft. tall and 1–3 ft. wide, with leathery gray-green leaves. Many flower stalks bear reddish pink blossoms in spring. Self-sows.

Penstemon pinifolius

Native to southern New Mexico and Arizona. Woody-based growth to 1 1/2 ft. high and 2 ft. wide, with short, needlelike bright green leaves crowded along the stems. Red-orange summer flowers. For rock gardens and borders or as a small-scale groundcover. Good in dry gardens or regularly watered ones.

Penstemon pseudospectabilis

Native to the mountains of Southern California and Arizona. Shrubby, upright plant grows to 2–4 ft. tall and 2 ft. wide. Large bluish green leaves with bases that clasp the stems. Rosy pink to purple flowers from spring into summer.

Penstemon richardsonii

Native to the Pacific Northwest. Woody grower to 1–1 1/2 ft. high and wide, with toothed, blue-green foliage. Rose, pink, lavender, or white flowers bloom in late summer for an extended period. Grows well in many climates. Tolerates some shade and may self-sow.

Penstemon rupicola

Native to the Cascades and Siskiyou Mountains. Woody-based growth to 4 in. high and 1 1/2 ft. wide, with trailing, much-branched stems. Small, roundish blue-green leaves have finely toothed edges. Bright rose flowers bloom from late spring into summer. Beautiful in rock gardens or chinks in dry stone walls.

Penstemon spectabilis

Native to Southern California. Grows to 3–4 1/2 ft. tall and wide, with smooth green or grayish leaves that clasp the stems. Rose-colored to purplish flowers in spring, early summer.

Penstemon strictus

Native from southern Wyoming to Arizona and New Mexico. Grows to 2–3 ft. tall and 2 ft. wide. Dark green leaves turn purplish in winter. Blooms in early summer, producing large blossoms in near-violet to brilliant bluish purple. Long-lived and adaptable.

Penstemon triflorus

Native to central Texas. Herbaceous plant grows to 1 1/2–2 ft. high and 1–1 1/2 ft. wide, with rich green foliage. Pink, rose, or white flowers bloom in spring. Long-lived and adaptable, performing well in the Southwest and also in more humid areas.

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