Penstemon heterophyllus ‘Electric Blue’ (Foothill Beardtongue)

Penstemon heterophyllus ‘Electric Blue’ is a dazzling perennial that produces masses of brilliant blue to violet flowers. Its narrow, pointed foliage starts out with a bluish tinge, transitioning to green, providing a dramatic backdrop for the luminescent flowers.

Penstemon heterophyllus ‘Electric Blue’: An In-depth Look

Native: This cultivar originates from the species Penstemon heterophyllus, which is native to the western United States, particularly California.

Plant Type and Habit: It’s an evergreen perennial that forms tidy clumps. This penstemon maintains a bushy, upright habit with a slightly spreading nature.

Size: ‘Electric Blue’ typically grows to a height and spread of 12-18 inches (30-45 cm).

Flowers: The tubular flowers are a stunning electric blue to violet, often with a slightly paler throat, and are borne on slender, erect, red stems. Their vibrancy is a highlight in any garden.

Bloom Time: The bloom period is relatively long, starting in late spring and continuing through mid-summer.

Foliage: The foliage is narrow, pointed, and bluish-green, becoming more green as the season progresses. Its evergreen nature in milder climates adds year-round interest.

Uses: Given its striking color and form, ‘Electric Blue’ is used as a focal point in borders, rock gardens, and containers. It’s also used in native plant gardens and pollinator gardens.

Hardiness: It is hardy in USDA zones 6-10, showcasing both heat and moderate cold tolerance.

Pollinators: Penstemon attracts various pollinators, especially bees, butterflies, and hummingbirds, drawn to the nectar-rich flowers.

Toxicity: Penstemon heterophyllus ‘Electric Blue’ has no significant known toxicity to pets or humans.

Deer and Rabbit: Penstemons, including ‘Electric Blue’, are generally deer-resistant and somewhat resistant to rabbits, though heavy infestations can cause damage.

Drought: It’s noted for its drought tolerance once established, requiring little water in the right conditions, aligning with its native habitat’s environment.

Invasiveness: ‘Electric Blue’ is non-invasive, sticking to its defined space in the garden.

Penstemon Growing Tips

Light: Full sun (at least 6 hours of direct sun per day). Tolerates light shade.

Soil: Well-drained soil is crucial. Penstemons prefer rocky or sandy lean soils rather than rich garden loam. Avoid overly moist, poorly drained soils.

Water: Water well until plants are established. Once established, Penstemons tolerate some drought. Allow the soil to dry out between waterings. Over-watering or wet soils can lead to root rot.

Fertilizer: Penstemon plants generally do not require heavy fertilization and can thrive in relatively lean soil conditions. However, providing them with a light application of an organic fertilizer in the fall can help boost their growth and flowering potential.

Pruning: Deadhead spent flowers to encourage continuous blooming. Cut back plants in late autumn or early spring to promote vigorous growth.

Mulching: Mulching Penstemon can help regulate ground temperature and suppress weed growth. Choose a mulch that does not hold water. Use organic materials like shredded bark, compost, or pine straw. Avoiding direct contact with the stems to prevent rot and pest issues.

Propagation: Propagate by softwood cuttings in mid summer or semi-hardwood cuttings in summer

Pests and Diseases: No serious pest or disease issues, but watch for slugs, snails, and nematodes. Fungal diseases can occur in overly wet conditions; ensure good air circulation and avoid overhead watering to prevent issues like powdery mildew, leaf spot, and root rot. Rust can cause small, rust-colored pustules on leaves and stems, leading to defoliation and stunted growth.