Jeremy Bartlett's LET IT GROW blog

Drama and beauty amongst the shingle

Sea-kale, Crambe maritima, is starting to flower on the south coast of England and will continue throughout late spring and early summer around our coasts.

When it grows in quantity Sea-kale can dominate the shorescape. In Flora Britannica, Richard Mabey describes the appearance of Sea-kale plants from a distance as “like enormous sea-urchins, or a rounded desert cactus that has taken to the shingle” and, closer to, having “something of the character of outsize cauliflowers” (note 1).

Like Sea Pea, Sea-kale is abundant at Shingle Street in Suffolk, and adds drama to a visit to this special place.

Sea-kale, Crambe maritima. Shingle Street, Suffolk. May 2023.

I also associate Sea-kale with seaside holidays to the Isle of Portland in Dorset, Rye Harbour in East Sussex and Dungeness in Kent.

Sea-kale, Crambe maritima. Isle of Portland, June 2023.

Prospect Cottage, Dungeness (Derek Jarman’s home from 1987 to 1994), with Sea-kale, Crambe maritima. September 2010.

Where to find Sea-kale

Sea-kale (or sometimes ‘Sea Kale”), Crambe maritima, is a tough plant of shingle and boulder beaches and occasionally sea cliffs and is found around suitable coasts in the British Isles, where it is a native plant. It is a halophyte (it is tolerant to salt) and has a long, fleshy tap-root to provide anchorage and reach scarce water supplies.

Sea-kale has declined in some parts of its range where sea-defence works have destroyed its shingle habitats. Violent winter storms can destroy plants and the use of bulldozers to rebuild shingle banks can cause damage too and perhaps for this reason, the plant is less common in North Norfolk than on some other coasts.

However, given the chance, Sea-kale can recover from buried root fragments or seed even when established plants are damaged and the BSBI Plant Atlas 2020 gives its overall distribution as either stable or increasing. Sea-kale has increased in Ireland since the 1960s and several sites have been found along the Antrim coastline, where the plant had not been recorded for over 200 years.

Distribution map of Crambe maritima from BSBI Online Plant Atlas 2020.

Further afield, Crambe maritima is native in many other European countries, north to Scandinavia and east to the Caucasus, Ukraine and parts of Russia and Turkey. It has been introduced into Czechia and Slovakia, and the state of Oregon in the United States.

In North Norfolk, Sea-kale seed was sown on Blakeney Point in 1912, resulting in a single plant which survived until the 1953 storm surge destroyed it. Plants re-appeared on the Point in 1968 and several plants persisted (note 2). I photographed some of them in 2009.

Sea-kale on Blakeney Point, North Norfolk. October 2009.

The plants present in 2009 were destroyed by northerly gales and huge shingle movements in 2010 but Sea-kale plants reappeared on the shingle within 10 years and in 2025 there were 26 plants in total. It’s possible that movements of Land Rovers or tractors helped to distribute their seeds or roots, as all these plants were close to vehicle tracks (note 3).

A year in the life of Sea-kale

Crambe maritima is a perennial plant. It dies back in winter back into its fleshy taproot and the new shoots that emerge through the shingle in the spring are often tinged purple but become blue-green as the leaves expand.

Sea-kale, Crambe maritima, at Rye Harbour, East Sussex. Late April 2013.

The plants produce sprays of flowers from mid spring onwards, pale cream in bud and white when fully open. Each flower has four petals arranged in the shape of a cross, typical of the Brassicaceae (Cabbage family), and the reason for the older name for this family of plants, the Cruciferae. The flowers are deliciously honey-scented and attractive to humans and insects alike.

Close up of Sea-kale, Crambe maritima, flowers.

Sea-kale, Crambe maritima (with Sea Campion, Silene maritima). Shingle Street, Suffolk. May 2023.

Seed-heads form after flowering and remain well into the autumn and early winter, until flattened or removed by storms.

Crambe maritima seeds are egg- (or pea) shaped and float on water, so can be spread to new locations on the tide. (See the Wild Flower Finder website for close up pictures of the seeds and for other superb photographs of the plant.)

Young plants can take at least five years to produce flowers.

Sea-kale, Crambe maritima. Rye Harbour, September 2010.

Eating Sea-kale

Sea-kale is an edible plant. The older leaves are rather bitter and not very pleasant but the young leaves have a “pleasant almost nutty flavour” and can be eaten raw or cooked. The best flavoured shoots are those that have been blanched (covered to exclude the light). This can happen naturally where shoots have been covered by shingle but locals would sometimes cover young shoots with seaweed or sand. The young flowering shoots can be steamed in the same way as sprouting broccoli. The root is edible too, according to the Plants For A Future website. Galloway Wild Foods suggests dipping young shoots in Wild Garlic pesto, which sounds delicious.

The Galloway Wild Foods website offers very sound advice, a collector’s code for anyone picking Sea-kale in the wild. Please do follow it if you wish to pick the plant.

“Uprooting of sea kale seems like a very poor prize at a high cost, and should not be done. Individual plants, or isolated groups of just a handful of plants should be left alone. Young purple shoots and florets can be sustainably harvested from healthy colonies by removing just one or two from mature plants, then moving on.

Flowers and seed pods should be harvested with similar restraint, being sensitive to the relative abundance of the plants. If in doubt,  consider observing the colony for a few seasons, so you gain an understanding of how it is doing. As always, thinning abundance should be a responsible forager’s mantra!”

If in doubt, don’t pick!

As an edible plant, Sea-kale has gone through periods of fashion. In the late 18th century the plant was highly prized by London society and fresh shoots and even roots and seeds were sold at Covent Garden in London. At the end of the nineteenth century whole cartloads of plants were being collected on the Isle of Man (note 1). Simon Harrap has suggested that this over-harvesting contributed to a massive decline of the plant in Norfolk by the mid nineteenth century (note 2).

Growing Sea-kale

I have never harvested Sea-kale from the wild, but I have grown it on my allotment and in doing this I inadvertently followed the example of the great naturalist Gilbert White, who gathered seed in Devon in August 1750 and sowed it in his garden at Selborne in Hampshire the following April (note 1).

I covered my single fairly small plant with a bucket in early spring to exclude light from the shoots and it provided us with small crops of blanched shoots for a couple of years. I think it was worth growing and we liked the gentle slightly nutty flavour of the blanched shoots.

Sea-kale plants are often long-lived but my plant died after a couple of years, perhaps after being weakened by club root, which is a problem on our allotment site. But I might have another go at growing this useful drought-tolerant plant.

Crambe maritima will grow in full sun or partial shade in fertile, very well-drained soil, with enough space to let the plant spread and enough depth to accommodate the long tap root. It is very hardy and will survive our coldest winters.

Sea-kale is not suitable for growing in shallow containers, but the Hartley Botanic website suggests using tubs, which can be brought indoors to provide early shoots. (They’d have to be large tubs and you’d need lots of space. Alternatively, small, deep pots may work.)

The Gardenersworld.com, Hartley Botanic and Royal Horticultural Society (RHS) websites offer advice on growing Sea-kale. Plants or pieces of root (“thongs”) can be bought online and Emorsgate Seeds supplies seeds.

A 2014 article in The Independent newspaper gives an account of Sea-kale being grown commercially in Britain.

Other species of Crambe

As well as Sea-kale, Crambe maritima, two other species of Crambe can be found growing wild in the British Isles.

Greater Sea-kale, Crambe cordifolia, is an even more spectacular perennial plant. From its mound of long-stalked, puckered, bristly dark-green leaves it produces a frothy mass of sweetly scented white flowers on long stems. It makes a spectacular plant for the back of a garden border. It is occasionally found as a garden throwout, where its roots persist but it rarely seeds. I planted it in Grapes Hill Community Garden in Norwich, where it was stunning for the first year – and then Garden Snails destroyed it.

Abyssinian Kale, Crambe hispanica, is sometimes grown as a spring-sown oil-seed crop (as subspecies abyssinica).  It occasionally escapes onto waste ground, road verges and riverbanks. It was first noticed in the wild in 2003 (Berwickshire) and in Ireland in 2008 (County Tyrone) and is increasing. I haven’t seen it yet.

Notes

Note 1 – Richard Mabey, pp 155 – 157, “Flora Britannica”. Sinclair-Stevenson, 1996.

Note 2 – Simon Harrap, p31, “Flowers of the Norfolk Coast”. Norfolk Nature Guides, 2008.

Note 3 – Richard Porter, “The plants of Blakeney Point: recent changes in status”. In Transactions of the Norfolk & Norwich Naturalists’ Society volume 58, part 1 (2025).