Sea kale, Crambe maritima, is a striking plant that is both ornamental and edible. The large leaves are a lovely glaucous green, with wavy edges, and in summer these are crowned with a cloud of tiny white perfumed flowers. These nectar-rich flowers are great for attracting pollinating insects. 
For best results, grow sea kale in full sun or partial shade in fertile, very well-drained soil. The position needs to be deep enough to accommodate the long tap root of the plant with plenty of space for it to spread out. Sea kale is not suitable for growing in containers. 
The round bullet-like seeds have a hard, outer casing, so soak seeds and score to remove this before planting the seed in compost with a little bit of heat. Alternatively, young plants can be grown from root cuttings. Plant out young sea kale plants in early spring, into a well-prepared bed that is the final position for these perennial plants as they don’t like being moved.