[D. grandiflorum] 'Dragon's Head'
Low growing perennial with dense racemes of bright-dark blue flowers produced in midsummer over 12 inch tall plants. Stems purplish tinted, numerous and ascending. Plants form a carpet 15 inches wide. Best is a sunny location with some midday shade in fertile, well-drained soil. Blooms early to mid summer. In China plants are used as a Tea substitute and grown for its large, purple-blue flowers.
Zones 4-8. Native from China and Mongolia were it is found in alpine meadows, grassy slopes, sunny areas in sparse forests. This species is often sold under the name D. grandiflorum. One way to tell the two species apart is that the petioles of the middle cauline leaves are 2-6 cm long on the true D. grandiflorum - while D. rupestre has very short or no petioles.