These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area. For example, early spring is generally a good time for pruning many shade trees. It's easy to see what needs to be pruned since the leaves are off. It's best to complete pruning before buds break, however.
Early spring can be a good time for some deciduous shrubs to be pruned, and a poor time for others.
Consider when the shrub blooms. If it's a spring bloomer, wait until just after flowering to prune or you'll be cutting off flower buds. When pruning evergreens, knowing what species involved is essential. Perhaps the best example of suggested spring pruning on an evergreen would be major pruning of yew or juniper. Do this in early April, right before new growth starts to occur.