Pruning Native Plants

by Allison Levin

California native plants can be used in every garden style: formal, Japanese, architectural, you name it. But even when the garden is "wild and natural," gardeners usually want to know about pruning their trees, shrubs, vines, perennials and grasses. Over the year, I'll be writing about when, why, and how to prune various California plants in the garden. In particular, I'll be writing about trees and woody shrubs.

Arbutus menziesii. Photo by Doreen L. Smith.

Ask Yourself Why

When you think about pruning any plant, ask yourself what do you want to change, and what do you want to achieve? Are there branches that are dead or rubbing against each other? Do you want the plant to stand out as a focal point in the garden? Has it become too leggy? Do you want to control its size?
As you think about why you want to prune, don't expect to achieve everything at once. Plants are the controlling partners when it comes to their form, size, and growth. If you take your time, you'll learn how each species responds to pruning. Make pruning plans that are two, three, and five years in the making.

Check the Calendar

The time to prune a plant is very important, for a few reasons:
Pruning weakens a woody plant, because it takes away part of the plant's food source (leaves); it also creates a wound that the plant needs to heal. To minimize these two aspects, prune when the tree (or any woody plant) is dormant -- AND when it is just about to start pushing out new growth. That's because, with that new growth, healing tissue starts to form, beginning the process of covering the wound with healthy tissue. (Of course, removing dead wood doesn't weaken the plant at all, and can be done at any time.) And, pruning just before a plant leafs out results in a more beautiful plant. New growth hides any awkwardness that pruning cuts might make. One way to anticipate the onset of new growth is to observe a plant's flowering. Notice that, as the tree's flowers fade, new foliage begins to emerge.

Because so many of our California woody plants are dormant in summer and do their growing when the rain kicks in, the deep of winter is usually the wrong time for pruning. Exceptions to that rule include pines and arbutus. For these species, plan on making any needed structural cuts in December or January. Annual, finer pruning work on pines can be scheduled for October or November.

Next: March and reconstructive pruning for deciduous trees.

(This article is first in a series of pruning articles from Allison Levin. See Part 2 | Part 3 | Part 4)

Allison Levin is an aesthetic pruner and native plant consultant living in Sausalito and working in the greater SF Bay region. You can send her comments or questions for this series at grownatives.cnps.org