Crambe cordifolia

This unique perennial is in the Brassica family - related to cabbage, kale, broccoli, and more. When it flowers, it can shoot up to an impressive 7 feet tall! You'll need plenty of space for it to grow, but you can expect a dazzling display of airy white flowers in early summer.

Flowering sea kale is a great choice for a mixed perennial border or cottage garden. It does best in rich, moist soil. It might wane in the heat and humidity of summer. Due to its long taproot, avoid transplanting.