IN my Jan. 18 column I discussed winter pruning.
Based on the number of emails I received, it seems to have generated considerable interest for gardeners who prune during winter.
Most of the questions I received were based on "why" and "how" we prune. So to clarify and expand for everyone who prunes during the winter, here's the why of it and some how-to as well.
Firstly, clean tools are happy tools and any Jedi gardener worth his or her salt knows that clean pruning tools cut faster, easier and make cleaner cuts.
Cutting faster and easier is also better ergonomic action for the human wrist and arm muscles and tendons, which makes the work less laborious.
How you clean your pruning tools is quite simple using a technique that I innovated way back when I was the director at Park & Tilford Gardens as a means to teach students proper care of their tools.
To clean your hand pruner, saw, or lopper you'll need some waterproof sandpaper for metal in 300 or 400 grit. Some sandpaper brands only say "fine," "medium" or "coarse," so choose fine.
You'll also need Lysol disinfectant spray, the non-foaming type used as a disinfectant spray for air and many household surfaces.
It is non-CFC to help protect our atmosphere's ozone layer. This product is a good killer of many bacteria; it's less effective with viruses. Its limitations are not an issue because we are using sandpaper in combination.
Spray both side of your tool's pruning blade and the anvil liberally with the Lysol Then take a small piece of the sandpaper and rub firmly on the blade/anvil working in small circles or back and forth, using the Lysol as a lubricant and disinfectant to remove plant residue. When the Lysol becomes dryish, use a rag or paper towel to wipe off the residue and respray. Continue until both sides of the blade and anvil are silver and shiny.
The Lysol disinfects and the sandpaper mechanically removes all plant sap residues, thereby removing all possible pathogens from the tool to allow for disease-free pruning. Even though Lysol may not kill many plant viruses, the mechanical action of hand-sanding removes any potentially infected plant residue from the tool. When done, hold the pruner close enough to hear the swishing action of a clean pruner, which is the sound of Jedi cleanliness. The advantage of this type of "field cleaning" over other methods is portability in the field, relatively non-toxic, cost effective, self contained and easy to do.
The frequency of cleaning depends on how much work is done, if there is diseased plant tissue present and individual preference. I clean my tools before I prune in a new garden to prevent spread of disease from a previous garden, whenever the tool becomes sticky or difficult to operate, and between known to be diseased plants and any other plant.
The next question that readers asked was why not prune some trees in winter and if not winter, then when?
There are several deciduous trees that do not take kindly to winter pruning such as all Japanese maples, birch, Japanese stewartia, some cherries that are diseased, twisted hazel or willow and dogwood.
The first reason not prune those trees is to prevent the growth of those uncharacteristically straight suckers that grow after winter pruning caused by dormant season invigoration response. The second reason is to avoid vascular diseases that attack stem and branch during our wet winters, sometimes caused by using dirty pruning tools.
The time to prune those trees is during June or July, August at the latest. Summer pruning affords drier weather and sunlight and both of those environmental conditions help to sterilize pruning wounds and prevent disease infestation.
Another question that readers asked: How do I prune my rhodos? Only prune if you have a reason.
Rhodos generally do not require annual pruning except for dead or damaged tissue. A well placed rhododendron can be left alone to grow to its maximum size and virtue without much pruning.
It is important to know that many rhodos grow to be large shrubs and pruning them down into small balls is a crime against nature and ignores their genetic programming to be large plants. In China, many rhodos grow as tall as 24 metres and they are trees. So choose your plant wisely or transplant existing rhodos to better locations to avoid pruning. And winter pruning of rhodos removes flowering wood.
Readers also asked about fruit tree pruning, which is somewhat complex and should be done for specific reasons. Winter pruning of fruit trees causes invigoration and strong regrowth and it is used to build structure. Summer pruning of fruit trees controls vigour and helps even density without the strong regrowth.
Todd Major is a journeyman horticulturist, garden designer, writer, consultant and organic advocate. [email protected]
