Crambe maritima is a lovely dual purpose plant. This delicacy from the olden days is a relative of the cabbage; it can be grown as a vegetable. Available in the spring, the flowerbuds can be eaten like broccoli. Blanched shoots and young leaves can be eaten raw or the leaf midribs cooked and eaten like Asparagus. With a unique delicate flavour, somewhat like hazelnuts and a crisp texture, forced Seakale is a real delicacy. Two or three crops can usually be harvested each year.
In the garden, it can be grown as an eye-catching and fragrant border plant. It has perhaps the most beautiful of all large glaucous leaves; the wide blades are exquisitely curved and lobed. It is superb in the border and ideal for cutting. In early summer, abundant clusters of honey-scented white flowers are held above the wonderfully ruffled, leathery, blue-green leaves. Hardy to about -20°C (-4°F) tolerant of both salt air and drought. The flowers are highly attractive to bees.
If you have an exposed area of the garden where little else will grow consider Seakale as it will happily grow and turn non-productive ground into productive ground.
- Awarded the RHS Award of Garden Merit
Crambe maritima has been awarded the Royal Horticultural Society’s Award of Garden Merit (AGM).
Sowing: Sow at 15°C (59°F) in spring or autumn
Remove outer seed casing to speed up germination, sow in pots, trays, direct sow or into a nursery bed. Use well drained soil and sow seeds 12mm (½in) deep. Germination usually takes place in 3 to 5 weeks at 15°C (59°F) but can be slow and irregular and can take a few months. If sown indoors, prick out the seedlings into individual pots as soon as they are large enough to handle
Plant out into their permanent positions when about 10cm (4in) tall. Plant 75cm (30in) apart in rows 75cm (30in) apart. Provide a rich, deep and sandy soil and position in a place where it is exposed to at least a few hours of direct sunlight. Seakale is a close relative to Brassicas so avoid planting in soil infected with clubroot. Clear any dead or damaged foliage as required. Young plants are attractive to slugs so some protection may be needed. Plants can be cropped once they are more than 12 months old.
Seakale is a perennial and can be forced and blanched where it has grown (meaning the same plants can be used for several years) or, in order to produce an early crop of shoots, the roots can be lifted in the winter, brought into a greenhouse and grown on there (resulting in the plants being discarded after forcing); forcing in situ is therefore the most practical way.
Forcing In Situ:
Any time after the leaves have died right back, from autumn until January. Clear away the old leaf debris and cover the crowns with about 7.5cm (3in) of dry leaves which will help to insulate the crown. Cover the individual crowns with buckets or similar (traditional clay seakale forcing pots are perfect but virtually impossible to find). They should be around 30cm (12in) in diameter and at least 38cm (15in) tall and must completely exclude the light. Ensure they are firmly held down so they do not blow away.
Shoots are usually ready for cutting within 3 months and ideally should be 15 to 23cm (6 to 9in) long when cut. Use a sharp knife to cut them low down with a little piece of root attached. Stop cutting in May and uncover plants allowing them to re-grow. They can then be forced again the following season.
Dig up the crowns after the first frost. Pot up into gritty compost or pack into boxes or crates and place in a greenhouse or cool room. Exclude all light with buckets, up-turned pots or similar. Cut shoots as they appear, ideally at about 10 to 20cm (4 to 8 in). At the end of the season you will more than likely need to dispose of the plants.
Plants can be divided in spring or autumn. Dig up the root clump and cut off as many sections as you require, making sure they all have at least one growing point. The larger of these divisions can be planted out straight into their permanent positions, though small ones are best potted up and grown on in a cold frame until they are established.
A long lived plant, they will deteriorate and need replacing after 5 to 7 years of cropping (i.e. approximately ten years from when first started).
The pods do not open to let the single seeds fall out, but drop off, and the seeds germinate around the parent plant. Any seedlings that appear may be moved while they are still small.
Crambe maritima had its place in many a medieval menu. Along the coast of England, where it is commonly found above High Tide Mark on shingle beaches, local people heaped loose shingle around the naturally occurring root crowns in springtime, thus blanching the emerging shoots.
A few years preceding 1765 the seed were sold at a high price as a rarity. It was first employed in the garden about 200 years ago, and the practice spread to the continent where it became a delicacy.
By the early 18th Century it had become established as a garden vegetable, but its height of popularity was the early 19th Century when sea kale appeared in Thomas Jefferson's Garden Book of 1809, and was served at the Prince Regent's Royal Pavilion in Brighton.
Sea kale is now very popular in English markets and is largely used in France.
Young leaves can be eaten raw or cooked like spinach. They go well in a mixed salad and make a very pleasant cooked vegetable. The harvest of its leaves can be ongoing throughout the season.
The shoots are served like asparagus, steamed, with béchamel sauce or melted butter, salt and pepper.
Used like sprouting broccoli, the flowering shoots are harvested when about 10 to 15cm long and before the flowers have opened, raw or cooked, they are delicious when lightly steamed. The root can also be cooked.
Especially useful in dry, sunny sites, grow it alongside other maritime species.
Sea Rocket, Sea Purslane, Sea Milkwort and Sea Holly.
Crambe maritima is a perennial of coastal sands and shingles of northern Europe and Baltic and Black Seas. It is generally restricted to the top of the beach and is therefore, a rare plant. It may, however, be locally abundant where it is found forming impressive colonies. It is declining in Britain, partly owing to reduction of its habitat but mainly because of sea-defence work. The plant is protected under the Wildlife & Countryside Act (1981) and must not be picked without permission from the landowner.
The pods are blunt or egg-shaped, the seed is dispersed by seawater, on which it can float for several days without loss of viability.
The name Crambe, is from the ancient Greek Krambh, the name given for a cabbage like plant.
The species name maritima, meaning 'of the sea' and the common name of Seakale, or Sea Kale refer to the plants native habitat.
There are a number of sea vegetables that are considered to be delicacies in modern cuisine. Their nutritional value, taste and ease of growing make these crops incredibly popular.
Known as Halophytes or 'salt-tolerant' plants, they have adapted to grow in grows in areas of high salinity either directly in salt water or in coastal areas. They are not ‘salt-loving’ plants and do not have to be grown in saline environments.
Crops such as Salicornia (Sea Samphire), Crithmum (Rock Samphire), Sea Kale (Crambe), Salsola komarovii (Okahijiki) and Salsola soda (Agretti), Sea Aster (Aster tripolium), Sea Beet (Beta vulgaris subsp. maritima), Tetragonia (New Zealand Spinach), Saltbush (Orach) and Alexanders (Smyrnium) can be grown at home or foraged from the wild.
- Awarded the RHS Award of Garden Merit
- Additional Information
Average Seed Count 10 seeds Seed Form Natural Seeds per gram The size and weight of these seeds vary considerably. Common Name Seakale, Wildflower of Britain and Ireland
Other Common Names Sea Kale Other Language Names IR. Praiseach thrá Family Brassicaceae Genus Crambe Species maritima Cultivar Lilywhite Hardiness Hardy Perennial Flowers White Natural Flower Time June to August. Foliage Large glaucous leaves; the wide blades are exquisitely curved and lobed. Height 60 to 75 cm (24 to 30in) Spread 60 to 75 cm (24 to 30in) Position Full sun or part shade Soil Deep, fertile, well-drained soil, Time to Sow Sow at 15°C (59°F) in spring or autumn Harvest Shoots should be 15 to 23cm (6 to 9in) long when cut.