Culture
Best grown in rich, sandy to gravelly, neutral to alkaline, medium moisture, well-drained loams in full sun. Tolerates light shade. Established plants tolerate some drought. Although native habitat is maritime conditions above the high water mark, this perennial adapts well to borders and vegetable gardens. Add lime to the soils as needed to maintain neutral/alkaline character. Propagate by seed or root cuttings.
Noteworthy Characteristics
Crambe maritime, commonly known as sea kale, is a robust mustard family perennial that typically grows in a spreading basal mound to 30-36” tall and to 24-30” wide. It is native to coastal sea shore areas of Europe from the north Atlantic through the Mediterranean to Asia Minor and around the Black Sea. It is grown for ornamental purposes (attractive blue-green foliage and white flowers) and/or as a vegetable (edible leaves, stems, flowers and roots). Large, fleshy, glaucous, shallowly-lobed, ovate-oblong, wavy-edged, basal leaves (to 2’ long) resemble the leaves found on collards and cabbages which are in the same family. Leaves are the main ornamental attraction. Leaf mound is covered in June-July by a profuse bloom of small, fragrant, 4-petaled white flowers (to 1/2” wide) in dense panicles (corymbose racemes). Flowers are followed by almost spherical pea-like seed pods to 1/4” wide. Each pod has one seed.
Sea kale is a popular vegetable in parts of Europe (particularly England and France), but has never caught on in the U. S. Shoots are typically cut in spring when 8” long, blanched, steamed and eaten (like asparagus). Young leaves may be eaten raw or cooked (like spinach). Flower buds may be eaten raw or cooked (like broccoli). Roots may also be eaten raw or cooked (boiled or steamed).
RHS Award of Garden Merit in 2002.
Genus name comes from the Greek word krambh which was the name of a cabbage-like plant in ancient Greece.
Specific epithet comes from the Latin word maritimus which means growing by the sea in reference to the native habitat of this species.
Problems
No serious insect or disease problems. Watch for slugs and cabbage moth caterpillars in some areas.
Uses
Dry sunny areas. Borders. Cottage gardens. Vegetable gardens. Containers.