The pruning class, given by Cass Turnbull of Plant Amnesty sponsored by the division of Community Forestry and several other agencies, was the most well attended gardening type class I have seen in Juneau. The speaker set the tone for the evening by revealing that the longer she gardened, the less she pruned. She empowered the audience to join her in moving more shrubs than she pruned and killing more than she moved.
David Lendrum is a master gardener and owner of Landscape Alaska. Responses or questions can be sent to www.landscapealaska.com.
This brought a gasp from her audience, since what she was able to replace in a couple of seasons in Seattle would probably take the rest of our lives to regrow here. Her point was taken though, there is only so much you can do with an ugly, misplaced shrub and when you have exhausted the tenderer possibilities, there is always one left. Euthanasia.
Cass spoke as if the people in the room were her old friends, and they all knew just what she was talking about. The goal of home gardening was to have things nice, make them look pretty and diminish the amount of work one has to do. One of her concepts was to be able to prune the tops of many types of shrubs right down to the ground and let them grow back as healthy, rejuvenated gems. Many of the shrubs that we prize in Juneau are of the type that this works with. Sitka roses, spiraeas, ash-leafed spiraeas, and dogwoods, lilacs, chokecherries, high bush cranberries and clove-scented currants can all be sawn off a couple of inches above the soil line and given a good dose of chicken manure. They will respond by shooting up dozens of new branches, all vigorous and bursting with potential. The gardener can then pick and choose among all these possibilities and shape a new shrub that will bloom strongly and have leaves all the way down to the ground.
These shrubs can also be taken back a little at a time, in a manner called renewal pruning, so that the whole dramatic effect is never felt. One can prune a third of the branches back to the ground each season and in a few years all the growth will be the new young stuff.
This will not work however on a class of shrubs called small trees and treelike shrubs. These are plants like rhododendron, azalea, Japanese enkianthus or blueberries and menzesia. They can be identified by their branching structure. They look complicated, no simple arching canes growing from the ground, and they have thicker trunks and branching patterns that look like little trees.
They need more sensitive pruning, with the first step being removal of the dead wood. This is like visual static, or white noise, when you remove it with your hand pruners you are astounded at how much better it looks. It is also so much better for the plant, since it doesn't have all that vulnerable tissue hanging about waiting for the fungi to get started.
This is really the main reason we prune, to keep plants healthy and attractive. Pruning will not keep a big plant small forever, and if the plant was planted in the wrong place, like in front of your main view window, all the trimming in the world will not make it stay small. Every time you trim back the top, new buds start up and you get twice as many branches as before.
Cass called these hydra-headed shrubs, for the monster who grew back three heads every time Hercules cut one off. A good example would be a big bridal veil spiraea that covered part of the window, a conscientious pruner could trim back the offending branches weekly, and it would be OK, but never go on vacation. Sure as shooting, a little trip to Cancun would mean a major effort when one returned.
The pruning of trees was only slightly touched on, but three main styles were described. First was to thin, removing whole branches at a time while keeping the basic shape intact. This is for Norway maples, lindens and northern red oaks. It keeps them from becoming top-heavy or crowding out lower growing plants. The second style is for fruiting trees. They each call for a special series of cuts to keep the center open and fruiting wood healthy, and third is pruning to the ground, as in "Timber." Her point is that topping only ruins trees.