Although it is tempting to cut back everything to within an inch of its life in the great garden tidy up in autumn/winter, Cornus are shrubs which need leaving until the spring. Just before the leaves appear in early spring is the right time to cut their stems almost down to the ground. The stems will then grow quickly and leaf up during the summer. It is only in the autumn once their leaves fall that you will be able to see the glorious, young and brightly coloured stems which have been produced by the pruning you did back in the spring.