A Brief Lesson on Pruning Trees and Shrubs

This winter in the Chicago area has been a brutal one with extreme cold and plenty of snow. Usually I hear the first ambitious cardinals singing this time of the year, but I think they're even having second thoughts. However, the sun is climbing higher in the sky each day, so there is still hope to get out of this winter. With that said, this is the best time of the year to prune trees and shrubs.
October through April are prime times for pruning most trees and shrubs. The plants are dormant and not actively growing, which reduces stress and spread of disease. With the branches being bare in the winter, it is also easier to find broken and dead branches, or other structural issues. Some people wait until February and March to prune to not expose the cut to bitter cold. However, anytime in the fall and winter would be just fine.

The blade of the saw is just above the swollen area known as the branch collar

When pruning trees and shrubs, consider their blooming time. Lilacs, redbuds, viburnums, magnolias, and other spring-bloomers develop their flower buds in late summer prior to their bloom time. If you prune branches in the winter, you will remove the flower buds! To avoid this, prune these plants immediately after flowering in the summer when they are still actively growing.
Before pruning, make sure you are using clean tools to reduce the spread of disease. It's always important to prune stems back close to a bud, or node. When pruning branches on trees and large shrubs, cut back as close as you can to the area called the branch collar. This swollen area at the base of the branch is full of living tissue that heals the wound relatively fast (in plant terms). Cutting into the branch collar slows down the healing process. If you leave too much of a portion or stem above the node or branch collar, it will increase the chance of infection in the plant.
Consult a professional arborist if branches are too large, too high, or if you are just not sure what to do. This is a very brief look at pruning, so if you are looking for further information, here is a great link to look at:
http://www.mortonarb.org/trees-plants/plant-clinic/horticulture-care/caring-plants/pruning/pruning-trees.
Pruning is important to remove any unnecessary branches, train a young tree, or to shape a tree or shrub. It will also help if you want to increase flower production. Overall, it will help improve the health of your plants, and improve their longevity so you can enjoy them for years to come.

Photo Sources:
http://www.telegraph.co.uk/gardening/gardeningadvice/6563482/How-to-prune-vines.html

http://dnrtreelink.files.wordpress.com/2013/01/branch-collar-saw.jpg

Notice how the cut is being made just above the bud (node)