Sea Kale

Sea kale (Crambe maritima) is a striking architectural plant for coastal and gravel gardens, forming impressive mounds of blue-grey, ruffled foliage up to 60cm across. Its clouds of honey-scented white flowers in summer attract pollinators. Excellent for naturalistic plantings, it provides year-round structure and pairs beautifully with other drought-tolerant perennials. The sculptural seed heads extend seasonal interest into autumn.

Historically, sea kale leaves were used as an antiscorbutic to prevent scurvy due to their vitamin C content. The plant contains glucosinolates with potential anti-inflammatory properties. Traditional coastal communities used poultices of crushed leaves for treating wounds and rheumatic complaints. The young shoots were considered a spring tonic, believed to cleanse the blood and improve digestion after winter.

Young blanched shoots are a prized delicacy, harvested in early spring with a nutty, asparagus-like flavor. Force shoots under terracotta pots for tender, pale stems. Young leaves can be eaten raw in salads or cooked like cabbage. The flower buds, similar to broccoli, are edible when lightly steamed. Blanched stems are excellent grilled with butter or incorporated into risottos.

Native to European coastlines, sea kale stabilizes shingle beaches and sand dunes with its deep taproot system. It's highly attractive to bees, hoverflies, and butterflies. The plant provides habitat for coastal invertebrates and its seeds feed birds. Critically important for specialized shingle ecosystems, it's legally protected in many regions. Tolerates salt spray and extreme weather, making it valuable for climate-resilient planting.

Perennial forming clumps up to 1m tall and wide. Distinctive blue-grey, waxy leaves are deeply lobed and cabbage-like, with undulating margins. Produces masses of four-petaled white flowers in rounded clusters from May to July. Develops round, corky seed pods on branching stems. The thick, fleshy taproot can reach 2m deep. Distinguished from other brassicas by its glaucous coating and coastal habitat.

Sea kale is not used for timber or building purposes as it's a herbaceous perennial without woody growth. However, its dried stems have historically been used in coastal communities for kindling and tinder. The robust dead flower stems can be incorporated into rustic garden structures like temporary plant supports or decorative wreaths, though they decompose within a season.

Sea kale was cultivated by Thomas Jefferson at Monticello and was a fashionable Victorian vegetable before falling from favor. The plant can live over 10 years, unusually long for a brassica. Its seeds remain viable while floating in seawater for days, enabling coastal colonization. Once nearly extinct in Britain due to overharvesting, it inspired some of the first plant conservation laws in the 1920s.