Chelone, commonly called turtleheads, is a genus of four species of perennial herbaceous plants in the family Plantaginaceae (order Lamiales), native to eastern North America. The genus takes its name from the Greek word for "turtle-like," a reference to the distinctive shape of its flowers, whose fused petals form a closed, rounded corolla strikingly similar to a turtle's head. Flower color ranges from white through pink, red, and purple depending on species.
Plants grow to roughly 1 metre in height and bear opposite, toothed leaves. Blooms appear in late summer and early autumn, making Chelone a valuable late-season source of nectar. The four species — Chelone glabra, C. lyonii, C. obliqua, and C. cuthbertii — differ in chromosome number and distribution: the first three are diploid while C. obliqua is either tetraploid or hexaploid depending on locality. Molecular evidence suggests the four species diverged relatively recently, and C. obliqua appears to have arisen multiple times from diploid ancestors.
Chelone glabra (white turtlehead) is the most widespread, ranging from the Gulf States north to Newfoundland and west to Manitoba. The remaining species are confined to portions of the Appalachian Blue Ridge and Atlantic coastal plain of the southeastern United States. In cultivation, turtleheads thrive in moist to wet soils and tolerate heavy clay and partial shade, making them well suited to rain gardens, bog margins, and woodland edges. They are notably cold-hardy, surviving temperatures as low as approximately −20 °C.
Etymology
The genus name Chelone comes from the Greek word meaning "turtle-like," an allusion to the distinctive closed, rounded shape of the flowers, which closely resemble a turtle's head. This common name — turtlehead — is used for all four species in the genus.
Distribution
Chelone species are endemic to eastern North America. Chelone glabra has the broadest range, extending from Georgia and Mississippi north to Newfoundland and Manitoba. The other three species are geographically restricted: C. lyonii is found in the Blue Ridge of Tennessee, North Carolina, and South Carolina; C. cuthbertii in the Blue Ridge of North Carolina and the coastal plain of Virginia; and C. obliqua in the Blue Ridge, Tennessee–Arkansas–Michigan, and the Atlantic coastal plain from South Carolina to Maryland.
Ecology
Turtleheads grow naturally along streambanks, in wet meadows, boggy ground, and moist woodland edges throughout eastern North America. They prefer consistently moist to wet soils and tolerate heavy clay and semi-shaded conditions. Their late-summer flowers are a known host for the larvae of the Baltimore checkerspot butterfly (Euphydryas phaeton), a relationship that ties the genus to wetland ecosystems where both species coexist.
Cultivation
Chelone species are straightforward garden perennials given adequate moisture. They perform best in light loam but tolerate heavy clay; they prefer moist to wet conditions and will not thrive in prolonged drought. A bog garden or rain garden setting suits them well. Plants grow well in semi-shade to full sun and are exceptionally cold-hardy, surviving to approximately −20 °C (USDA zones 3 and above). Because they spread freely at the roots, growing them in a large container can limit their spread in smaller gardens.
Propagation
Chelone can be propagated by seed, division, or cuttings. Sow seed in a cold frame in spring, keeping the medium consistently moist; germination occurs in 2–6 weeks at 20 °C. Prick seedlings into individual pots once large enough to handle, and plant out in spring or early summer. Established clumps may be divided in autumn. Softwood cuttings taken in summer root readily in sandy medium in a cold frame.
Cultural Uses
Chelone glabra was used extensively in North American folk medicine under the common name Balmony. The whole herb was prepared as a decoction valued as a bitter tonic for the liver and digestive system, and was employed for liver disease, gallbladder problems and gallstones, intestinal colic, and as a vermifuge. It was also reported to have mild antidepressant and laxative effects, and was used in the treatment of anorexia nervosa for its tonic action on digestion. Externally, preparations were applied to haemorrhoids, inflamed tumours, and irritated skin. These uses have long standing in folk tradition but have not been investigated scientifically.
