One of the major causes of anxiety among amateur landscapers is the subject of pruning shrubs. After all, you’ve invested a fair amount of time and money in them, and now you’re expected to cut chunks out of them?! Eeeek!
If it puts you mind at rest, think of pruning more along the lines of giving your shrubs a haircut, rather than performing major surgery. If nothing else, it sounds a lot less drastic. I am always happy to provide personal answers to your specific questions about pruning (or any other landscape issue). Meanwhile, here are some brief answers to common pruning questions.
Why should I prune my shrubs?
The main reason for pruning should be to maintain the health and safety of your shrubs. Frankly, if you are simply shearing off parts because they’re impeding the driveway or blocking light to a window, you probably started off with the wrong plants in the wrong places.
You can help your shrubs stay healthy by pruning away the three “D’s” ... dead, dying and diseased sections of the plant. Removing these problem parts will play a large role in keeping your shrubs healthy.
What are the basics of shrub pruning?
First, it helps to understand two different types of pruning cuts. These are known as thinning cuts and heading cuts.
Thinning cuts are made at what’s known as the point of origin. The intention is to reduce the density of the shrub and discourage regrowth at that point. Heading cuts are a little more creative. Your objective is to stimulate growth of the buds closest to the wound.
Here’s the thing to remember about heading cuts: The direction in which the top remaining bud is pointing will determine the direction of new growth, according to the authors of “A Guide to Successful Pruning” published online by the Extension Service of Virginia Tech. You can read the entire text and see diagrams at the Web site listed at the end of this column.
When making a heading cut, prune about one quarter of an inch above the bud. The cut should slope down and away from the bud. When you find yourself pruning above two or more buds, the rule of thumb is to remove the ones facing inwards. There is no need to paint the cuts with wound dressing because it won’t help wound closure or prevent decay.
When should I prune?
Prune at different times of the year and you’ll get different results. As you might guess, most shrubs are best pruned in that brief period of late winter / early spring, before the buds break. When it comes to most spring-blooming plants, many horticulturists (including those at the Virginia Tech Extension Service) suggest waiting until after flowering. This allows you to enjoy the floral display before you trim.
When it comes to summer-blooming shrubs, you can prune in early spring prior to bud set or in summer after the shrub has flowered.
Think carefully and/or consult a horticultural advisor before pruning shrubs in late summer or early fall. Reason: You will promote vigorous growth which might not be tough enough to withstand cold winter weather conditions in many areas.
Any additional information available?
There are numerous Web sites offering pruning information. Here are two sites that are particularly helpful. In fact, I referred to both of them while writing this column. http://www.ext.colostate.edu/pubs/garden/07206.html and http://www.ext.vt.edu/pubs/nursery/430-459/430-459.html. If you are at all unsure about how to make the cuts, refer to the diagrams at these sites or drop me a line.