Crambe maritima

Sea Kale Brassicaceae

Crambe maritima — Sea Kale, proving that vegetables needn’t look as though they belong in the allotment. This handsome maritime perennial forms a broad mound of thick, wavy-edged, glaucous leaves, followed in early summer by great clouds of small, honey-scented white flowers. Native to the coasts of Europe and extending to the Caucasus, it is perfectly at home in poor, sandy or shingly soils and positively enjoys the sort of exposure that would have lesser vegetables reaching for their umbrellas. 

It is also a genuinely excellent edible. The young spring shoots are traditionally blanched and cooked like asparagus, developing a delicate, nutty flavour with a hint of hazelnut and a pleasant crispness. Young leaves can be eaten raw or cooked, while unopened flowering shoots can be treated much like sprouting broccoli. (British Ecological Society Journals⁠) The trick with the shoots is to force established plants from their second year onwards: in late winter or early spring, cover emerging shoots with an upturned bucket or forcing pot to exclude light. After several weeks, harvest the pale shoots when around 10–15cm long. Steam or simmer gently until just tender, then serve with butter, salt and pepper — essentially asparagus, but with considerably more seaside credentials. 

The flowers are richly supplied with nectar and pollen and are excellent for bees and other pollinating insects, earning C. maritima a place on the RHS Plants for Pollinators list.  Give it full sun, excellent drainage and room to develop; it is remarkably tough once established and particularly good in coastal, gravel and naturalistic planting.

Flowering: June–July
Hardiness: H7, below –20°C
Height: 50–75cm
Spread: 30–60cm
Edible: Young forced shoots, young leaves and unopened flowering shoots; cook shoots like asparagus and flowering shoots like sprouting broccoli