Clump-forming, to 30cm across with age. Leaves rosetted, ovate-oblong to obovate, 8-18cm long, toothed, hairy, thick-textured, deep green. Flowers 2.5cm across, tubular, with five flared petal lobes, the upper two smaller than the rest, lilac to violet-blue, fading with age, the yellow throat bearing violet speckles, in cymes of up to five, late spring to early summer. Mountains of Bulgaria and adjacent Greece, in rock crevices. H.r. var. ferdinandi-coburgii is somewhat larger in all its parts, with leaves glabrous, or almost so above. H.r. 'Virginalis' has pure white blooms.