In early May, when other perennials are just awakening, Epimedium x. setosum sends up charming blooms in white. Though their flowers are delicate, epimediums are hardly frail. They're virtually carefree, and take well to dry shade -- something that very few plants do with ease.

The white flowers of Allium 'Mount Everest' seem especially magnificent when they rise high above a patch of humble dame's rocket (Hesperis matronalis). The lichen-covered Russian olive tree is skirted by lamb's ears (Stachys byzantina 'Big Ears') and multiple creamy globes of low-growing A. karataviense 'Ivory Queen.'

White Wisteria floribunda 'Longissima Alba' plays off purple alliums, deep magenta primulas, and hot-pink geraniums to create an idyllic spring moment. In the background, a cluster of self-sowing dame's rocket (Hesperis matronalis) presents a moment of calm.

Early-blooming Solomon's seal (Polygonatum odoratum 'Variegatum') flowers white in spring. Its white variegated foliage brightens the shade for the rest of the season.

Corydalis ochroleuca is a mild-mannered, self-sowing, shade-loving perennial that comes in pristine white.

Because its blossoms emerge from buds on new stems, Hydrangea arborescens 'Annabelle' puts on a grand show, despite hard winters and late frosts.

The abundant creamy-white bracts of Cornus florida 'White Cloud' open before the leaves emerge. Gracefully rounded, this dogwood cultivar grows about 20 feet tall and wide.

Cornus x 'Celestial' belongs to the Stellar Series of hybrids, crosses between C. kousa and C. florida bred in the 1960s by Rutgers University plant breeder Elwin Orton. Twenty feet tall and 14 feet wide, 'Celestial' has a distinctive vase shape. Its leaves appear before the blossoms, which usually begin to open after the first week of May.