Penstemon digitalis Nutt. ex Sims
Foxglove Beardtongue, Foxglove Penstemon, Smooth Penstemon, Talus Slope Penstemon
Chelone digitalis, Penstemon laevigatus subsp. digitalis, Penstemon laevigatus var. digitalis
Bloom Time: Late spring to early summer
Penstemon digitalis is a glabrous herbaceous plant with simple shiny green leaves that grow on slender purple stems arranged in opposite pairs. The leaves are up to 5 inches (12.5 cm) long. While upright, the stems average anywhere from 2 to 3 feet (60 to 90 cm) tall. The flowering panicle extends to almost one-third of the plant's height and has pairs of branches that repeat with two flowers multiple times. The pedicels are nearly one-fourth of an inch (2.5 cm) long and produce 1.25 inches (3.1 cm) long, two-lipped, tubular flowers over dark green foliage. The flowers are white and borne in late spring to early summer. The plant has elliptic basal leaves and lance-shaped to oblong stem leaves.
USDA hardiness zone 2a to 8b: from −50 °F (−45.6 °C) to 20 °F (−6.7 °C).
How to Grow and Care
The best location for your Penstemon is a full-sun area with well-draining soil. Penstemon care and maintenance are minimal if the site and moisture requirements are met. Poorly draining soils and freezing temperatures while the plant is still active are the biggest causes of plant mortality.
The perennial is remarkably tolerant of drought conditions and is a stalwart presence in even low-nutrient soils. It has had to be adaptable to thrive in windy, exposed areas of mountain foothills.
You can grow Penstemon from seed. They begin as rosettes low to the ground before forming the characteristic flower stalk. Indoor sowing should begin in late winter. Seedlings are ready to transplant when they have a second set of true leaves. Space Penstemon plants 1 to 3 feet apart and mix in a little compost at planting time to help conserve water and increase porosity.
Water the young plants at least once per week as they establish. You can reduce watering as the plant matures. Mulch around the plants to help protect the roots from winter's cold and prevent spring weeds.
See more at How to Grow and Care for Penstemon.
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