Native to Turkey and Iran and at its best in cool, dry summers, pincushion flower is a plant of rocky meadows that has found an appreciative audience in well-drained cottage and perennial borders. Its genus name traces back to the Latin for "the itch," a nod to the rough texture of its leaves, but there is nothing irritating about its behavior: it settles into a tidy clump, 2 feet tall and wide, and produces its soft blue or white flower heads with remarkable persistence from early summer to frost. Full sun and gritty, alkaline soil are its two non-negotiable requirements.

Heat and humidity are its enemies, and in warm coastal gardens it tends to short-lived. A light, dry winter mulch of straw or evergreen boughs helps it through cold spells in marginal zones. Deadheading spent flowers prolongs the show considerably, and division in spring every few years keeps the clump vigorous. The cultivar Butterfly Blue, with its lavender-blue flowers on 20-inch stems, is usually more available than the straight species and is every bit as good.