In my travels through mid Michigan I talk with a lot of people. I may be meeting with them to discuss a new landscape design or to look at a plant that is sick or dying. No matter what I am meeting them for, we often discuss their garden as a whole. One of the categories of questions that seems to come up the most often is pruning. How do I prune this plant? When do I prune this plant? In my first article I touched on pruning a little bit and so I thought I would go into more depth now.
To answer the question posed in the title of this article, its both. Science is involved because we have to know the culture of the plant to know when to prune. We also have to know the botany of the plant to know how it will respond to the pruning. Science also helps us to know what needs to be pruned out. A tree or shrub may have a disease that needs to be removed and the pruner needs to know how far below the disease or injury he or she should prune. Art is involved, because we enjoy our landscapes aesthetically and we want our plants to be pleasing to the eye. This may include pruning that most of us are not qualified to do for example, topiary or bonsai.
Let’s get down to the facts of pruning. The first rule of pruning is to remove any dead or dying branches. How do I know its dieing? Look for sunken areas, small leaves, areas that are soft to the touch, or a discoloration in the bark. You may also see galls on certain shrubs or trees that need to be pruned off. If you have any of these conditions, you will need to cut at least 1″ into healthy tissue to avoid the pest spreading to the rest of the plant. You should also sterilize your pruners between cuts to avoid transmission of the organism to healthy tissue. This is easily accomplished by inserting your pruners into a bath of alcohol. It is important when you are pruning to always cut back to a node. What’s a node? A node is an area of the plant where a stem, bud or leaf comes out. Pruning just above the node with out leaving any stubs on the branch will avoid further death to the branch. After you are done removing the dead and dying branches its time to look for crossing branches. If branches cross they will rub against each other and create a wound or could eventually grow together and create a weak area that will break in a storm. Once we have removed the crossing branches its time to look at the overall shape and size of the plant. For trees you may want to limb them up so you can mow under them or you may want to thin out the canopy some to let more light in. Whatever your desires are for that tree, just remember to go slow, stand back and look often, and always prune back to a node as we discussed earlier. The reason I say to go slow and look often, is because you can always take more off but its really hard to put it back on. Next week we will discuss shrub pruning, timing, and how and why to perform renewal pruning on shrubs.