Ostrowskia magnifica

The magnificent, stupendous, mystical Holy Grail of campanulads, this denizen of rocky crags in the Pamir-Alai produces impossibly large, 5-inch-wide, pure white bells on strong stems that can reach 5 feet tall. It does best in full sun; deep, gritty, humus-rich soil; and a relatively arid climate (but it’s well worth trying elsewhere!). Steppe/Montane; C Asia. Zone 4.