If I were a forager one of my favourite green vegetables grows in large clumps in the shingle beach nearby where I live, just ripe for harvesting: but Richard Harrington at the Marine Conservation Society urges people to cultivate it themselves. With a new garden - not yet planned, but with an increasing number of ornamental plants already purchased - the space for many vegetables is becoming more limited. However the structure of the leaves allows it to be incorporated as a 'structural' plant somewhere in the scheme of things and this is almost certainly what we will do.
In Victorian times it was a popular vegetable. I remember being served curly kale as a child. The Victorians piled stones and sand around the plants so as to harvest the whitened stems for market. It is labour intensive and fiddly if grown for the commercial market.
I have read that the plant should grow for three years before being harvested. With a mixed flavour of asparagus and cauliflower it is - apart from it's vitamin C content a useful addition to the table. The tough leaves should be blanched before frying...I have yet to try.