Campanulaceae: Campanulastrum americanum
Family Name
Campanulaceae
Common Name
American bellflower
Description
Campanulastrum americanum is a biennial or short-lived perennial herb. It grows from a slender, fibrous root system and does not spread vegetatively by rhizomes or stolons. In its first year, it forms a basal rosette of ovate to elliptical leaves (5 to 12 centimeters long and 3 to 8 centimeters wide), with long petioles (1 to 5 cm) and coarsely toothed margins. In its second year, a single, erect, and usually unbranched stem rises, ranging from 60–150 cm tall, hairless to sparsely hairy, and often tinged with purple near the base. Cauline leaves are alternate, Stem leaves are smaller, lanceolate to ovate, ranging from 2 to 7 centimeters long and 1 to 4 centimeters wide, sharply toothed, and gradually decreasing in size up the stem; petioles are shorter than on basal leaves or absent on upper leaves. Flowering occurs from June to September. The inflorescence is a loose, terminal raceme or panicle, with large, showy, star-shaped flowers. Flowers are bisexual, each with five narrow green five fused sepals forming a green calyx tube about 5 to 7 millimeters long and 2 to 4 millimeters wide. The blue to violet corolla is formed by five fused petals with a flared mouth and five lobes, each petal about 1.5 to 3 centimeters long and 6 to 12 millimeters wide, deeply divided into five spreading lobes. There are five stamens with fused anthers forming a tube, and a single pistil with a three-lobed style and stigma. The fruit is an upright, cylindrical to oblong capsule (7–12 mm), ripening in late summer to fall, containing many tiny, brown seeds (less than 1 mm). American bellflower is native to South Dakota, especially in moist woodlands, shaded streambanks, forest edges, and rich alluvial soils, and is most often found in the eastern and southeastern regions, particularly in wooded valleys and the Coteau des Prairies.
Horticulture Notes
Seed Collection: Seeds are mature when capsules turn brown and begin to split open at the top; mature seeds are tiny, dry, and brown, typically collected in late summer to early fall.
Germination: Seeds require light for best germination; sow on the soil surface in fall or after a 2–4 week cold stratification period.
Vegetative Propagation: Not commonly propagated vegetatively; most plants are grown from seed.
Soils: Prefers moist, fertile, well-drained soils high in organic matter but is tolerant of a range of soil types.
Light: Grows best in partial shade but tolerates full sun in cooler climates.
Water: Requires consistent moisture for robust growth, especially during germination and flowering, but tolerates short dry periods once established.
Additional Notes
American bellflower is a native wildflower valued for its tall, showy spikes of blue flowers and is used ornamentally in native plant gardens and naturalized landscapes. It attracts native pollinators, especially long-tongued bees and butterflies.