Penstemon
( pen - STEEM - on )
At-A-Glance InformationCommonly called Beard Tongue, this genus of flowering perennial plants need partial shade in the warmest climates of their zone range, and little to moderate water. The flowers will attract butterflies and hummingbirds to your garden. These plants are native to the West, including down to Mexico and up to Canada. Some will grow in high deserts, others in mountain settings. Flowers can come in red, blue, soft pink, salmon, peach, deep rose, lilac, dark purple, white, and yellow (though this color is very rare). They live for about three to four years before needing to be replaced.
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Penstemon Species and Varietals
There are about 150 species included in the genus Penstemon. The growing zones for these plants vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.
Penstemon ambiguus (Prairie Penstemon, Sand Penstemon) This species grows in zones 2, 3, 7-15 and 18-21. They are native to the south-central southwestern areas of the United States and are woody-based, shrubby plants. Leaves are narrow and greyish-green and white and pink flowers bloom in large clusters. This species needs heat and sandy soil to perform at its peak, and will spread via underground stems if conditions are favorable. |
Penstemon barbatus (Scarlet Bugler)
This species is best in zones 1-20 and needs some cold during the winter months to perform well. It is native to mountain ranges in Colorado and Utah, southward to Mexico. It has an open habit and grows to 3 feet tall and a foot wide with bright green leaves. Flowers are red and form in large, loose spikes from late spring or mid-summer through the first frost of the year. Choice garden varieties are listed below.
This species is best in zones 1-20 and needs some cold during the winter months to perform well. It is native to mountain ranges in Colorado and Utah, southward to Mexico. It has an open habit and grows to 3 feet tall and a foot wide with bright green leaves. Flowers are red and form in large, loose spikes from late spring or mid-summer through the first frost of the year. Choice garden varieties are listed below.
Penstemon cutei (Sunset Penstemon) This species grows best in zones 2, 3, 7-14 and 18-21. It is native to northern Arizona and reaches 2.5-3 feet tall and 2 feet wide. Leaves are blue-grey and flowers are pink. This plant will bloom from late spring through to late summertime and is frequented by hummingbirds. Can self-sow under ideal conditions. |
Penstemon cobaea (Wild Foxglove, Wild Snapdragon) This species grows well in zones 2-11 and 14-24, and is native to the plains of Nebraska through to Texas. It reaches 1-2 feet tall and 1 foot wide, with dark green leaves and flowers in shades of white, pink, lavender and purple. Blooms appear in late spring or summer. This is a long-lived species that needs regular water. |
Penstemon davidsonii This species grows well in zones 1-7, 14 and 15. It is native to the Sierra Nevada Mountains up to British Columbia and forms a mat just 4-8 inches tall and 1.5 feet wide. Leaves are small and dark green and flowers are violet-blue and bloom in the middle of summertime. This species prefers a dusting of snow in wintertime and needs regular water. |
Penstemon digitalis This species is best in zones 1-9 and 14-24, and is native to the eastern and central regions of the United States. This plant reaches 3-5 feet tall and 2-3 feet wide, with long green leaves and white or pale pink flowers that bloom in clusters in summertime. Can tolerate some heat and humidity, and needs regular water. Variety 'Husker Red' reaches 2-3 feet tall with maroon colored foliage and pink-white flowers. |
Penstemon heterophyllus (Foothill Penstemon)
This species grows best in zones 7-24 and is native to California. It has blue-green foliage and spikes of reddish purple to deep blue blooms that appear in spring and early summer. The flowers attract bees. Popular varieties are outlined below.
This species grows best in zones 7-24 and is native to California. It has blue-green foliage and spikes of reddish purple to deep blue blooms that appear in spring and early summer. The flowers attract bees. Popular varieties are outlined below.
Penstemon Hybrids These grow well in zones 6-9 and 14-24, though they can be treated as an annual flower in all other zones. They are compact, bushy plants with loose flower spikes that appear in summertime. Blooms come in all colors except blue and yellow. Great when massed in border plantings, and can be pruned back for an encore bloom. They need moderate water, especially in late summer and early fall. Varieties are described below. |
'Alice Hindley'
Foliage has a sheen to it; flowers are pale lilac with white throats. |
'Firebird' ('Schoenholzeri')
This variety has scarlet flowers that bloom profusely. |
'Garnet'
('Andenken an Friedrich Hahn') Flowers are wine red on a plant with finely divided foliage. Long-lived variety that blooms profusely. |
'Hidcote Pink'
Profuse coral blooms with white throats streaked with maroon. |
'Kissed Series'
Large flowers in bright colors with white throats. Choice varieties in this group include 'Cerise Kissed', 'Coral Kissed', 'Violet Kissed' and 'Wine Kissed' (pictured). |
'Midnight'
Bushy, hardy plant with green leaves and dark blue to purple flowers. |
'Sour Grapes'
Flowers are a combo of metallic blue and violet, though some may have bright and red-violet blossoms. |
Penstemon pinifolius Native to southern New Mexico Arizona and best in zones 1-24; this woody-based plant reaches 1.5 feet tall and 2 feet wide, with bright green, needle-like leaves and summertime reddish orange flowers. Great for a small-area groundcover, for rock gardens, or for borders. Great with or without waterings. Varieties include 'Mersea Yellow' (1 foot tall and 1.5 feet wide with soft yellow flowers) and 'Shades of Mango' (a 15-inch tall plant with orange and yellow flowers). |
Penstemon pseudospectabilis (Desert Beard Tongue) This species is best in zones 2, 3, 10 and 12-21 and is native to the southern California mountains and Arizona. It has a shrubby upright habit and 2-4 feet tall and 2 feet wide. Leaves are blue-green and flowers are rose-pink to purple, blooming in spring through summer. This is a long-lived species that is easy to grow. |
Penstemon rupicola (Rock Penstemon) This species grows in zones 2-7 and 14-17, reaching 4 inches tall and 1.5 feet wide, with trailing stems. Leaves are bluish green, and toothed. Flowers bloom in spring and summer and are rose. Great for rock gardens or spaces in walls. Variety 'Albus' needs some shade for best performance. This species is native to the Cascade Mountains and the Siskiyou Mountains. |
Caring for Penstemon
All species need fast-draining soil, and prefer soil to not be too nutrient rich.
Propagation
Problems and Pests
Gallery
Videos
A video all about growing camellias successfully
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Propagating camellias
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 490 - 492, Penstemon
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