Start with shrubs
Shrubs are the most forgiving plants to prune because they are continually producing new branches to cover up any mistakes you may make. Trees need a little more care so be sure to consult a pruning book with diagrams before beginning. There are several good books on the market including Pruning Made Easy by Lewis Hill and The Pruning Book by Lee Reich. We also have a booklet on pruning at our office for $5.
When to prune
From the plants perspective, the best time to prune is when it is metabolically active so it can quickly respond to the pruning cuts. This is generally from mid March through mid July. Exceptions are when the plant is in bloom and the week when its first pushing out its new growth for the season. Avoid doing much pruning during these times.
In general, prune before the plant leafs out if you want to stimulate new growth or make big changes to the plants growth habit. Pruning before the leaves emerge invigorates plants. This is also a nice time to prune shrubs because you can see the branches more easily without leaves in the way.
Amy Ivy is executive director with Cornell Cooperative Extension in Clinton County. Office phone numbers: Clinton County 561-7450, Essex County 962-4810, Franklin County 483-7403.