Darkmar 21 is a traditional bedfordshire type, has a long cropping season,  December till March, is very popular variety with gardeners as the sprouts are large, deep green in colour, sweet and tasty.
 
An old English variety, By harvesting the lower sprouts first you can enjoy a steady supply without them all maturing at the same time and you will have a heavy yield of sprouts through the winter, even in the harshest of weather.
 
Darkmar 21 is an easy to grow, reliable sort with a fine flavour.