Corkscrew vines (Distictus buccinatoria) should be pruned lightly in late winter or early spring before new growth emerges. They don't require aggressive pruning and can be left to grow in their natural, twisted shape. However, if you want to control their size or shape, you can trim back long or straggly shoots to encourage bushier growth. You can also remove any dead or damaged branches. Avoid pruning during the growing season as it can reduce blooming.