Husker Red Penstemon (Penstemon digitalis ‘Husker Red’) is a distinctive perennial known for its striking appearance and resilience. Its deep burgundy foliage provides year-round visual interest, contrasting with the delicate white to pale pink, bell-shaped flowers that emerge in late spring to early summer. This plant is popular as a low-maintenance, hardy addition to diverse landscapes.
Site Selection and Planting
Selecting an appropriate site is important for establishing Husker Red Penstemon. It thrives in full sun, requiring at least six hours of direct sunlight daily to maintain vibrant foliage color and promote abundant flowering. The plant adapts to various soil types, including sandy, loamy, or amended clay, provided drainage is consistently good. Poorly drained or overly wet conditions can lead to root rot and should be avoided.
The best times for planting are spring or fall, allowing the plant to establish its root system before extreme temperatures. Before planting, prepare the site by breaking up the soil to a depth of 12 to 16 inches and incorporating organic matter like compost to improve soil structure and drainage. When placing the plant, ensure the crown sits at or slightly above the surrounding soil level to prevent moisture accumulation. Space plants about 15 to 18 inches apart for mature spread and adequate air circulation. After planting, water thoroughly to settle the soil around the roots.
Essential Care Practices
Proper watering is important for Husker Red Penstemon, particularly during its establishment phase. For the first growing season (approximately 8 to 10 weeks after planting), consistent moisture helps the plant develop a strong root system. Once established, the plant exhibits drought tolerance, preferring the soil to dry out between waterings. During warmer months, providing about one inch of water per week, applied at the base of the plant to keep foliage dry, helps encourage stronger blooming. Overwatering or soggy soil can lead to root rot.
Husker Red Penstemon does not require extensive fertilization, thriving in average to lean soil. An annual light application of a balanced, flower-promoting fertilizer (e.g., 7-9-5 or 0-10-10) can be beneficial in early spring if blooming diminishes. Use these at half the recommended rate and avoid high-nitrogen fertilizers, which promote leafy growth over flowers. Applying a 1 to 2-inch layer of mulch helps regulate soil temperature, retain moisture, and suppress weeds. Organic materials like shredded bark, compost, or pine straw are suitable, but ensure the mulch does not directly touch the stems to prevent moisture issues.
Pruning and Maintenance
Specific pruning techniques contribute to the ongoing health and appearance of Husker Red Penstemon. Deadheading, the removal of spent flower stalks, can encourage successive blooms and prevent excessive self-seeding. While ‘Husker Red’ may not rebloom significantly after deadheading, removing fading flower spikes improves tidiness. Cut the entire flower stalk back to the plant’s base once the main bloom cycle concludes.
Foliage maintenance involves cutting back the plant to promote vigorous new growth and maintain a neat appearance. This can be performed in late autumn or early spring, reducing the plant to 3 to 4 inches above the ground. This practice rejuvenates the plant and prepares it for the upcoming growing season. Division can promote plant vigor and offer new plants for propagation. Husker Red Penstemon clumps can be divided every three to four years, ideally in the spring, by carefully digging up the clump and separating it into smaller sections, each with healthy roots and shoots, before replanting.
Troubleshooting Common Problems
While Husker Red Penstemon is generally robust, it can encounter a few common problems. The plant is largely pest-resistant, but occasional issues with slugs, snails, nematodes, or aphids may arise. These can be managed with appropriate horticultural practices or targeted treatments if infestations are severe. More commonly, problems stem from environmental conditions rather than pests.
Diseases are often linked to improper watering or poor air circulation. Root rot results from consistently wet or poorly drained soil. Powdery mildew and leaf spot can develop in humid environments or when plants are too crowded, restricting airflow. To prevent these fungal issues, ensure good air circulation around plants and avoid overhead watering, directing water to the soil level. If wilting occurs, it could indicate insufficient water or too much moisture leading to root problems, requiring a check of the soil’s moisture level.
Winterizing Husker Red Penstemon
In late autumn or early spring, Husker Red Penstemon foliage can be cut back. Some gardeners leave spent flower stalks and foliage for winter interest and natural insulation for the crown.
In colder climates, applying a dry winter mulch around the base of the plant can protect the crown from extreme temperature fluctuations and freezing/thawing cycles. Pine needles or shredded bark work well. Husker Red Penstemon is hardy and typically survives winter without extensive intervention, but this preparation helps ensure its robust return in the spring.