In the Garden:
A properly made pruning cut on this oak tree has healed rapidly and is now almost completely closed over.
A Cut Above
It is pruning season. These mid to late winter days are the best time to prune most trees, as well as vines and shrubs. The exceptions to this rule are those plants that only bloom in spring, which are best pruned after they complete their bloom cycle. Most folks that have gardened for a while or read about gardening are aware of that fact.
What most people are not aware of is the how and why of pruning. It is sort of like this; we know we should be pruning but standing there in front of the plant with our surgical instruments of choice in hand, we are at a loss as to where to begin to operate on the patient. What should go and what should stay?
The bold among us just chop, slice, and saw away until it "looks about right". The timid snip a bit here and there and walk away, not sure what just happened. It's okay if you find yourself in one of these groups. I understand. Been there, done that.
I don't want to complicate the issue or discourage even a brand new gardener from tackling the task. Yet there are many species and forms of our landscape woody ornamentals and much to learn about the best way to prune each of them.
Let's take roses for example. There are miniatures, hedge or shrub roses, hybrid teas, grandifloras, floribundas, climbers, and the list goes on. The first time I read a book or rose pruning I had to take some aspirin and go lay down for a while until my head stopped spinning!
All kidding aside, pruning is both an art and a science. My own pruning education is an ongoing process, so I encourage you to not be dismayed by a" right vs. wrong" set of rules but instead to set out to learn all you can about the best way to prune the plants in your landscape.
There are many great books, Web guides and Extension Service flyers instructing gardeners on the best ways to prune various plants. Grab what you can and build your pruning savvy year by year. Photos, diagrams, and videos are especially helpful, although I must confess that my plants never look like the ones in the diagrams and photos! So I'd like to offer a few thoughts to help with some general pruning concepts.
Heading vs. Thinning
First, pruning generally invigorates a branch, stimulating it to push out new growth. Where you cut matters when it comes to how the plant responds. When you cut a long shoot back part way the result is usually several new shoots emerging near the cut to "replace" the lost branch. This is called a "heading cut" and results in denser growth, making it ideal for creating a hedge or dense shrub.
When you cut back to where a branch joins another branch the result is less emergence of new vigorous sprouts but instead more direction of growth into the other branch. Think of a "Y" intersection and traffic diverted from one street to the other one. This is called a "reduction cut" or a "thinning cut" and helps reduce crowding while directing growth and plant shape. Thinning cuts are the preferred approach for most pruning done on ornamental trees and fruit trees.
Training vs. Maintaining
When a tree is very young our goal is to prune in a way that trains it into a strongly structured tree over time. This means making very purposeful cuts to establish the branches in a well spaced out, evenly distributed arrangement. What seems like a good distance when two branches are "thumb sized" may not when each is a foot in diameter! Also, branches don't get higher as the tree grows, so if you plan on mowing or walking under a tree make sure the lowest branch is at least six or more feet off of the ground where it attaches to the trunk.
Once a tree is several years old the training process starts to transform into maintenance. Much less pruning is needed if the plant was trained well at the start. Now the goal is to remove damaged, broken, or rubbing branches and perhaps do a little remedial training work here and there.
Stubs and Flush Cuts
This crash course on pruning -- uh, maybe I should rephrase that -- must also include a comment on stubs and flush cuts. In general, branches should be cut back to where they join another branch. More specifically, you don't want to leave a stub or it will just end up as dead wood that prevents the pruning wound from closing and healing over.
Likewise, if you cut too close to the trunk you will create a much larger wound that will heal very slowly. There is a natural ring around where a branch attaches. This area is known as the "branch collar" and is the tissue that is best able to close over a wound quickly. Cut just outside this branch collar.
One More Thing
When removing a branch that is too large or heavy for you to hold with one hand, don't just make one cut at the desired location or the weight of the branch will cause it to fall and strip away some of the bark down the trunk, leaving a nasty wound that will be very slow to heal. Do a Web search for "three cut method of pruning" for more on how to properly remove a large branch.
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