Boraginaceae: Phacelia hastata
Files
Family Name
Boraginaceae
Common Name
Silverleaf phacelia, silverleaf scorpionweed
Description
Phacelia hastata is a perennial herbaceous plant growing 15 to 60 cm tall from a fibrous root system with a woody base. The roots are slender and moderately deep, anchoring the plant in well-drained soils. Leaves are mostly basal and alternate along the stem, petiolate, with petioles 3 to 10 cm long. Blades are lanceolate to ovate-lanceolate, 5 to 15 cm long and 2 to 6 cm wide, often deeply lobed or toothed, covered with a dense layer of fine, silvery hairs that give the plant a distinctive silvery-gray appearance. The flowers are arranged in coiled cymes and bloom from May through August. Each flower has five fused sepals forming a calyx 3 to 5 millimeters long and about 1.5 to 2 millimeters wide, covered with fine hairs. The corolla is bell-shaped to funnel-shaped, pale blue to lavender, about 10 to 15 mm long and 6 to 10 mm wide, with five lobes at the mouth. The flower contains five stamens with prominent yellow anthers that extend beyond the corolla. The pistil has a superior ovary with a style about 6 to 8 mm long ending in a bifid stigma. The fruit is a small capsule containing several seeds. Silverleaf phacelia is native to South Dakota and is typically found in dry, open habitats such as prairies, rocky slopes, and sandy or gravelly soils, mainly in the western and central parts of the state.
Horticulture Notes
Seed Collection: Collect mature capsules in late summer when dry.
Germination: Seeds require cold-moist stratification for 30–60 days. Best sown directly in the fall into well-drained soil.
Vegetative Propagation: Mainly propagated by seed.
Soils: Prefers well-drained, sandy or rocky soils.
Light: Full sun.
Water: Drought-tolerant once established; prefers moderate moisture.
Additional Notes
Silverleaf phacelia is valued as a pollinator-friendly wildflower, attracting bees, butterflies, and other beneficial insects. The silvery foliage also adds ornamental interest to native plant gardens.