Seeds from Dianthus carophyllus King of Blacks. These herbaceous perennials thrive in full to part sun and well-drained neutral to alkaline soil. Clove-scented blossoms rise on slender stems above clumps of linear, grasslike, blue-green leaves. They bloom from late spring through midsummer, and may attract bees and butterflies. USDA Hardiness Zone 6 – 9.