Text and photos by Heli Fitzgerald

Sea kale (Crambe maritima) is a wild relative of an oil and fodder crop Crambe hispanica and also other brassica crops. It has a potential use in breeding, for example in proving salt or drought tolerance. Sea Kale grows as a native species across coastal areas of Northern and Baltic seas in Europe and on the coast of the Black Sea. 

In Nordic countries it grows on sand or shingle beaches in Finland, Norway and Sweden. Sea Kale can be found growing as single plants or scattered groups at the drift line on beaches. Its seeds can be dispersed by fruits blowing on the beach or by the sea because of the properties in seeds which enable them to float and stay viable in seawater for months. Algal drift on the beach aid the seed germination.  

Sea Kale used to be a commonly cultivated vegetable in France and Britain where it was first cultivated in castle and manor gardens but became more widely cultivated in private gardens in early 18th century. Later on Sea Kale almost disappeared from cultivation until new cultivation systems were developed in France, where there has been commercial production from 1988 onwards.  

Sea Kale has a high vitamin C content and contains anti-cancer properties as well as antiviral, antifungal, antiseptic and purifying properties. Historically, leaves were used in healing wounds, seed juice for gastritis and fruits for removing worms. The main way to eat Sea Kale is cooking its shoots the same way as asparagus, but all parts of the plant are edible. Young leaves and shoots have a nutty flavour. Sea Kale is also foraged by animals, fruits are eaten by birds and flowers are important for pollinator bees. 

Sea Kale is listed on Finnish, Norwegian and Swedish Red Lists as least concern. Elsewhere in Europe some populations are declining and in some countries it has even become extinct. The main threats affecting Sea Kale include trampling by humans, coastal development, suffocation by invasive species and the loss of its coastal habitats. Historically some populations in Europe have also been over collected. Its small and often isolated populations are vulnerable to destruction from natural and human threats. Climate change associated risks include a rising sea level and coastal defence works. 

References:  

Cultivariable, How to grow Sea Kale. Available at: https://www.cultivariable.com/instructions/other-vegetables/how-to-grow-sea-kale-and-other-crambes/ 

Korpelainen, H., Draper Munt, D., Magos Brehm, J., Labokas, J., Bulińska, Z., Strajeru, S., Smekalova, T., Eliáš, P. & Tavares, M. 2011. Crambe maritima. The IUCN Red List of Threatened Species 2011: e.T176431A7240134. Available at: http://www.iucnredlist.org/details/summary/176431/1 

Sanyal A. and Decocq G. (2015) Biological Flora of the British Isles: Crambe maritima. Journal of Ecology, Volume 103, Issue 3, pages 769-788. doi/10.1111/1365-2745.12389/full