Pruning trees is a lot like paying taxes. It’s an annual chore that you would really rather avoid. Even the thought of it may cause anxiety. You could do it yourself and save some money, but it sure is a lot easier putting the job in the hands of a professional.
You might even have the devilish thought of ignoring this obligation altogether, but you do so at considerable risk.
From now until February is the preferred time for pruning most trees, because this is the period of their dormancy. Ideally, all leaves will have fallen from deciduous trees, such as California sycamore and liquidambar, before you prune them, since total dormancy is not reached as long as some leaves are still attached. Still, throughout Los Angeles, deciduous trees are frequently pruned prior to complete leaf fall, and I have never seen any of them harmed as a result. Deciduous fruit trees (plum, apricot, apple), however, should be pruned at the end of winter, just before bud break.
Timing is everything
Earlier pruning could stimulate premature growth or flowering which, if followed by a frost, would be damaging to next year’s crop.
Certain tropical evergreen trees, such as weeping fig (Ficus benjamina), are best pruned just before growth resumes in late February or early March. Over the years, I have seen many weeping figs pruned in December or January that turned yellow immediately afterwards. Eventually, they got green again but only after many months had passed.
Particular tree species really should have caution tags attached to them when left unpruned from one year to the next.
Foremost among these are coral trees (Erythrina species). Anyone who regularly drives along San Vicente Boulevard near the ocean can testify to the potentially hazardous consequences of planting coral trees. Even with regular pruning, these most fragile trees — which grow in a broad median strip between Brentwood and Santa Monica — are subject to breakage of limbs. Because stocky limbs often branch out close to the base of the tree, the failure of one large limb is likely to pull the whole tree down along with it.
Eucalyptus trees are also famous for their brittle wood and instability. Because of their height, they are susceptible to wind damage. If planted near structures or in parkway strips or parking lots, they must be pruned annually or else their falling branches may cause damage to buildings or cars (or people) during a winter storm.
Carob trees in heavily watered parkway strips are also a hazard. During the last year, I saw two such trees break in half and crush vehicles parked on the street below. Carob trees are highly drought tolerant. In Israel, they live for hundreds of years without any water except for that provided by winter rain. When planted in lawns or other intensively irrigated landscapes, they are attacked by fungi that kill roots and weaken limbs.
How to do it
If you are going to prune a tree yourself, use the three-cut method for removal of large branches. The first cut is made from below (an undercut), no more than one-third of the way through the branch. This cut should be made a foot or more away from the trunk, depending on the branch diameter. The second cut (top cut) is made from above, in the usual manner, an inch to the outside of the undercut. While making the top cut, the branch will break back to where the undercut was made, without ripping off part of the trunk.
The third cut — made from above or below — removes the remaining stub but should be made at the branch collar (a swollen portion of the trunk at the branch base) and never flush to the trunk. In truth, pruning cuts on shrubs and roses should also be made at the branch collar. Flush cuts are invitations to bacterial and fungal pests.
To further prevent breakage, upright branches forming an angle of less than 30 degrees with the trunk should be removed, and no more than two branches should be allowed to grow out from a single point on the trunk. Horizontal branches should be at least 8 inches apart on the trunk.
TIP OF THE WEEK: S. Gere from Atwater Village e-mailed as follows:
“Awhile back, someone asked you about getting rid of asparagus fern. I have had success eradicating unwanted plants that thumb their noses at ordinary weed killers by using a product by Ortho called Brush-B-Gon, available at OSH. I used it to remove a whole fenceful of asparagus fern. Mixed with water, it is sprayed on the leaves of the unwanted plant.
“Just take care to drape foliage of surrounding plants while spraying. Leave the plant alone and, over the next few days, the leaves will carry the poison down to the roots and the plant will die. I also eradicated the stout suckers and saplings of a Siberian elm by pouring the product directly onto their stubs and into cuts I made in their woody roots.”
Photo credit: Rainbirder / Foter.com / CC BY-NC-SA