(Hollyhock) Create a colorful cottage garden with ‘Blacknight’ Hollyhocks. The deep purple-black, single blooms line the sturdy stalks midsummer. Standing up to 6 feet tall and spreading up to 2 feet wide, ‘Blacknight’ adds upright columnar height to your garden. Planted in full sun locations, Hollyhocks prefer average to fertile soil conditions. Hardy in zones 3-9, the midsummer blooms attract hummingbirds, butterflies, and pollinators. These fast-growing, easy-to-grow perennials make beautiful cut flowers. Plant in mass, or as a specimen, Hollyhocks provide a good backdrop for lower-growing perennials. We recommend planting Hollyhock ‘Blacknight’ up against a picket fence or wall. Although they have strong stems, we recommend support if planting them in a windy location.