Cascade Penstemon is a slender evergreen perennial featuring several unbranched stems emerging from a moderately woody base. These upright stems reach up to 28 inches tall and may be finely hairy. The broad, sharply serrated leaves are arranged oppositely along the stems, ranging from elliptic to lanceolate shapes. Lower leaves have petioles, while upper leaves clasp the stem directly. Flowering stalks bear single or up to five whorled flower clusters, each flower subtended by a hairy calyx. The blooms, appearing from June through early August, display a lavender to deep blue corolla. Enjoys sun or partial shade and moist, yet well-drained soils. This plant requires a good amount of watering, and it is ideal for gardens enduring long, damp winters. The flowers attract butterflies and hummingbirds.