Answer: None of these should be pruned now.
The Spirea japonica Little Princess and S. japonica Shirobana, as well as the bush cinquefoil or Potentilla can all be sheared off quite short in late winter or very early spring before they begins to grow. Remove any winter damaged stems and then trim more as needed to make the plant symmetrical, remove about two thirds of it. This helps it grow vigorously and stimulates blooming. Trim it again, but only lightly, after it blooms to encourage a second flush of flowers. These jobs can be done using a hedge shear or by hand.
The barberry has a naturally tidy shape and naturalyl small size and should not need much if any pruning. (It is a very low maintenance plant for this reason.) If you need to prune, do so in late winter to early spring.
Enjoy your shrubs!
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