Our local garden centres sells them in pack of 4 for a few pounds. They are an annual and will survive outside overwinter even in chilly Aberdeenshire! You can actually grow them from seed yourself if you want to though it too late for that this year.

Thats good, I fancied them for pots at the front door when my Cosmos gives up the ghost!

If you do try them from seed, the cabbages only colour up as autumn comes and they are chilled a bit. The purple or red frilly kales are really good for bedding, and for summer you ought to try Swiss Chard, Bright Lights, which come in various colours, or just Rhubarb Chard which is dramatic with dark red leaves. They all make good additions to summer bedding.

Bear in mind, though, that they're really intended to cover the period between now and up to about Christmas, maybe a bit before Christmas - they start to look rather unpleasant from then on, and will need replacing. They're sold for people to use as winter bedding, but rigorous gardeners know that winter bedding of this sort is really autumn bedding, needing replacing after 3 months, dating back to the old days when bedding was replaced every 3 months to fit with the seasons.