Crop Rotation Group
Fertile soil with excellent drainage, with a neutral to slightly alkaline pH.
Full sun to partial shade.
Yes, penstemons are hardy perennials, but hardiness varies with cultivar, so check plant tags. Well-rooted plants of the hardiest types can tolerate winter cold to -30°F (-34°C).
In spring, topdress the area around penstemons with rich compost or a balanced organic fertilizer.
Single Plants: 11" (30cm) each way (minimum)
Rows: 11" (30cm) with 11" (30cm) row gap (minimum)
Sow and Plant
Many penstemons can be grown from seed started in late winter indoors, which is the best way to start numerous plants for a wildflower meadow. Set seedlings out in spring, after freezing weather has passed. In more managed garden situations, consider buying named cultivars as starter plants, because the best characteristics of better perennial penstemons is preserved through vegetative propagation. Start with a purchased plant in spring. Penstemons more than three years old grow into clumps with young plants growing along the outer edges. These can be dug away and replanted to a new spot in early spring. Most penstemons also can be propagated by rooting non-blooming stem cuttings taken in summer.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.
Native to the American Southwest and Mexico, penstemons are distantly related to foxgloves and snapdragons, producing similar tubular blooms on upright spikes. The flowers attract hummingbirds and butterflies. Many cultivars derived from P. digitalis have red stems and foliage, adding to their visual impact in the garden. Size varies with species and variety, with mature height ranging from 12 inches (30 cm) to 5 feet (1.5 m).
Gather stems for use in cut arrangements when half of the flowers on a stem have opened. Removing old flowers can improve reblooming in many cultivars.
Penstemons have few problems with pests and diseases, but plants can succumb to root rot in overly wet conditions.
Planting and Harvesting Calendar
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Pests which Affect Penstemon