Basic information about Penstemon. Includes Origin, Growing & Cultivation, Common Pests & Diseases, Interesting Facts & Uses, and Garden Design Tips.
The botanical name, Penstemon, is derived from the Greek ‘penta’ meaning ‘five’ and stamen, the male flower part. Since it does have 5 stamens (which is unusual; they are usually of an even number) this is apt.
Penstemon is also the victim of a misspelling or corruption: John Mitchell published the first description of this plant in 1748 as ‘Penstemon’, which Linnaeus attempted to correct in 1753 to ‘Pentstemon’ as the better Greek use. Though Pentstemon is still occasionally used, Penstemon has become the accepted spelling (as well as being easier to say out loud!).
The common name, Beardtongue, refers again to that unusual fifth stamen; it is frequently infertile and in many species grows very long and hairy, protruding from the open ‘mouth’ of the flower.
Most species of Penstemon are native North America, with some representatives in East Asia.
Growing and Cultivation
Penstemon prefers full sun and well-drained soil. This plant will not tolerate ‘wet feet’ or heavy, soggy soils, but loves dry, hot areas and will grow in sandy, loose soils. After planting, water once a week and gradually taper off frequency and quantity of water. Once established, Penstemon will not need to be watered except in periods of extreme drought. It is not recommended to mulch with water-retentive mulches (wood chips, etc – due to its dislike of ‘wet feet’) although in cooler climates an insulating winter mulch of leaves, straw or other light, air pocket-filled material will help increase the chances of successful overwintering.
Do not overfertilize this plant, it is a only a light feeder. An excess of fertilizer will only produce foliage and/or may harm or kill the plant. This plant is a short-lived perennial, meaning it often fades out after 3 to 5 years; you may divide to recover plant vigor or save seed or cuttings to replant. Penstemon stems can be cut down in fall to tidy up the garden or left until spring (April or May) to be cut back to a few inches above the soil level. Pruning annually prevents the plant from becoming unattractively leggy and woody-stemmed. Deadheading spent flower stems is recommended to encourage rebloom throughout the season. Air circulation is very important to this plant; they hate to be crowded.
Common Pests and Diseases
Penstemon is very pest and disease resistant. The only occasional disease displayed is powdery mildew (whitish-gray powdery substance on leaf surface). This is typically caused by poor air circulation around the plant, and can be treated with fungicides and improved air circulation.
This plant is only partially deer and rabbit resistant – they may eat it or avoid it as they choose.
Interesting Facts and Uses
Some varieties and species of Penstemon are frequently used in xeriscaping, a type of landscaping that reduces the need for supplemental watering (popular in areas that need water conservation), due to its low water needs.
Penstemon were loved by Victorian gardeners who planted entire borders of mixed varieties of only Penstemons! Victorians were also active breeders of new varieties of Penstemon.
These plants are heavily favored by just about every pollinator – bees, butterflies, moths, and especially hummingbirds are all frequent guests to any bed! This is another excellent and almost essential plant for a pollinator-friendly garden.
Penstemon flowers can be cut to be used in floral arrangements and will last about a week in a vase.
Garden Design Tips
Penstemon’s tall large-flowered spikes contrast nicely with more rounded forms and make a beautiful backdrop for lower perennials, though they should still be seated close to the front of the border to enjoy. This plant harmonizes well with rounder flowers like daisies, asters, rudbeckias and roses.
To purchase varieties of Penstemon, please visit our Sun Companion Plants Page.