Penstemon digitalis ‘Husker Red’ is a highly valued cultivar of the native North American foxglove beardtongue. This plant is recognized for the dramatic contrast between its foliage and flowers, providing season-long interest in the garden. The lance-shaped leaves emerge in a deep, reddish-purple or maroon color, which holds best with sufficient sunlight. Complementing the dark foliage are tall, rigid spikes of tubular, white flowers, often with a faint pink blush, blooming from late spring into early summer. This clump-forming perennial is valued for its upright habit and hardiness across USDA zones 3 to 8.
Establishing the Ideal Growing Environment
The successful cultivation of ‘Husker Red’ penstemon requires maximum sun exposure, as this directly influences the intensity of the foliage color. Plants situated in full sun—at least six hours of direct light daily—will display the deepest maroon hues; those in partial shade may appear greener. The parent species, P. digitalis, tolerates humid, eastern North American climates, but site preparation is still important to prevent common issues.
The primary requirement for the planting medium is excellent drainage. While ‘Husker Red’ tolerates a wide range of soil types, including loam, sand, and clay, it cannot tolerate consistently wet or waterlogged conditions. Poor drainage leads directly to root and crown rot, which is the most significant threat to its longevity. This perennial performs better in lean, average soil rather than overly rich garden beds, which can lead to rapid, floppy growth that may require staking.
Planting and Initial Establishment
The best time to plant ‘Husker Red’ penstemon is either in the spring or the early fall, allowing the roots adequate time to establish before temperature extremes. When preparing the planting hole, dig it to the same depth as the nursery container but about two to three times wider. The plant’s crown should be set level with or slightly above the surrounding soil surface to ensure water sheds away from the base.
Proper spacing is necessary for long-term health, as mature plants can reach up to 36 inches in height and 18 inches in width. Space plants 18 to 24 inches between centers. After setting the plant and backfilling the soil, firm the area gently to eliminate air pockets and water thoroughly. Water regularly until the plant exhibits new growth and is fully established, which usually takes the first growing season.
Long-Term Seasonal Maintenance
Once established, the watering needs of ‘Husker Red’ decrease significantly, making it moderately drought-tolerant. During the late spring and early summer blooming period, deadheading the spent flower spikes is a beneficial practice. Cutting the faded blooms down to a set of healthy leaves encourages a tidy appearance and can sometimes promote a small rebloom later in the season.
The perennial’s foliage can be cut back either in late autumn after the leaves have died back or in early spring just before new growth emerges. Fertilization is rarely necessary, and over-feeding can weaken the plant structure. A light, balanced slow-release fertilizer can be applied in early spring only if the soil is notably poor. To maintain the plant’s vigor, division is recommended every three to five years, performed most effectively in the spring.
Addressing Common Issues and Propagation
The primary threats to ‘Husker Red’ are environmental, mainly relating to excessive moisture. Root rot is the most common issue, resulting directly from poor soil drainage or overwatering, often manifesting as sudden wilting or collapse. Fungal problems like powdery mildew can also occur, particularly in humid climates or when plants are overcrowded. This can be mitigated by ensuring proper plant spacing and air circulation. The plant is generally resistant to deer and rabbits, though minor garden pests like slugs and snails occasionally feed on the foliage.
Propagation is typically done through division or stem cuttings rather than seed, as seeds from a cultivar may not produce the characteristic red foliage. Division involves carefully separating the clump into smaller sections, ensuring each piece has a portion of the root system and new shoot growth. Softwood stem cuttings taken in the early summer can also be rooted to create clones of the parent plant.