Phylum: Magnoliophyta - Class: Equisetopsida - Order: Brassicales - Family: Brassicaceae
Gravelly sea shores are the natural habitat of many members of the family Brassicaceae including Sea Rocket. Changing the family name of this family of plants from Cruciferae to Brassicaceae (Cabbage plants) has done nothing for a group that already had quite a bad press. (Oilseed Rape, which causes allergic reactions in even normally healthy individuals, is an example.) It is therefore important to remember that some of our most loved garden plants and wildflowers are also 'cabbages' - Aubrieta deltoidea, for instance.
This coastal member of the mustard family is a pioneer species, colonising bare sand and shingle close to the splash zone where few other plants are able to survive. To cope with the shifting sand, Sea Rocket puts down a long taproot that branches and helps stabilise the sand.
Thick fleshy leaves to help this succulent plant to retain moisture, while its low growing form helps it cope with the impact of sand blown by strong coastal winds.
The four-petalled flowers, 10 to 15mm across, are mauve, pinkish or occasionally almost pure white.
Seed pods of Cakile maritima each comprise two compartments. The larger tip section, generally containing either one or two seeds, easily snaps off and falls onto the sand, thus ensuring that Sea Rocket plants grow there in future years. The basal compartment, usually containing a seed and sometimes two seeds, is buoyant and if waves smash a into plant this part of the seed pod can floatsaway on the surface of the sea and create a new colony where it drifts ashore.
Related species such as black mustard, rape and wild turnip are all very similar in form, having four flower petals and leaves with a bluish tinge; they too are commonly found near the coast but unl;ike Sea Rocket their flowers are yellow.
We hope that you have found this information helpful. If so we are sure you would find our books Wonderful Wildflowers of Wales, vols 1 to 4, by Sue Parker and Pat O'Reilly very useful too. Buy copies here...