Heathers need to be sheared after flowering. Use hedge trimmers and cut the entire shrub back just far enough to take off the spent flower heads. This will give the heather a neat, compact shape, eliminate the messy look of dead blooms and prevent the heather from dying out in the middle. Most pruning mistakes will cover themselves up after a season of good growth.
Plants that should be pruned from late winter into spring are plants that will bloom the following growing season, usually in summer, on wood produced in the previous growing season. These include abelia, Rose of Sharon (hibiscus syriacus), butterfly bush (buddleia davidii), caryopteris spp., shrub roses and Russian sage (Perovskia). If you do not cut back a butterfly bush, it will grow from where it left off last season. When it flowers, it will be a weak-kneed, top-heavy plant, 12 to 15 feet tall or more. Hard pruning every year will produce a well-shaped shrub that flowers vigorously in late summer or fall.
Prune shrubs grown for colored winter stems shortly before new spring growth begins. These include the shrubby dogwoods (cornus alba and cornus stolonifera), the bright, salmon-red salix britzensis and the ghostly white, stemmed bramble rubus cockburnianus. The key to successful pruning of all of these shrubs is to keep them eternally young; vigorous new shoots are longer and more brightly colored or bloom more freely than older, unpruned growths.
It is only natural to need to refresh your memory before tackling a job that you do so infrequently. That is why I recommend buying a soft-cover, basic pruning manual with plenty of clear pictures and taking it into the garden with you. Each time you are going to prune, do a quick review of that specific plant. Make it a part of your pruning habit on each outing, especially if you have a large yard with a variety of trees and shrubs or are particularly interested in the art of pruning.
Robb Rosser is a WSU-certified master gardener. Reach him at Write2Robb@aol.com.