My Weigela is messy and out of bounds. How and when do I prune it?
Many shrubs, including weigela, hate being cut back part way, and are better pruned thus: Remove a portion of the oldest stems near the base, to allow younger wood to develop fully. Weigela look a mess when cut back at midpoint, as do Buddleia.
If the weigela has really outgrown its space, cut the whole thing to about 12 inches from the ground right after flowering (or earlier spring if you like, skipping the bloom) and it will regrow.