I call this tree the Japanese Fuerte. I’d seen many pruned avocado trees, I’d pruned many avocado trees, and I’d read much about others’ pruning of avocado trees, but I’d never encountered an old tree that had been so consistently and artfully molded to a shape and size as this one. It was grown in the yard of a Japanese family living near San Diego. The day I met this tree was the day that affirmed what I had always imagined could be achieved over the long term by a visionary avocado tree pruner.
Despite being decades old, the tree is ten feet tall and twenty feet wide. The branch architecture reminds me of bonsai.
Why prune avocados?
We’re used to the idea of pruning other fruit trees, like peaches, but pruning avocado trees is not so familiar — for good reason. Unlike peaches, even if one never cuts a branch on an avocado tree, it can remain healthy and provide oodles of fruit for a century. (See the old trees at The Huntington, for example.)
But there are some good reasons to prune avocado trees, some situations where it’s advisable. I can think of three. One is to keep them down to size, whether in height or width. This was obviously the main objective of the pruner of the Japanese Fuerte. The tree had to be kept back from the fences and wall that surrounded it.
Another reason to prune is for balance. Some trees are determined to be lopsided, it seems. The danger of that is that they might fall over in high winds or under the weight of a lot of fruit.
(This is especially applicable to young trees. See my post on training young avocado trees.)
Pruning low branches that interfere with sprinklers is also a good idea. This is something that mostly needs to be done with young trees, but it has to be done or else the low leaves can entirely block the sprinkler’s spray.
Beyond these three good reasons to prune avocados, don’t do much fiddling. Removing upright shoots (sometimes called water sprouts) or dead inner branches can be done, but is unnecessary.
Best size or shape for an avocado tree
In terms of pruning an avocado tree for size and shape, is there an ideal that we should aim for? Is there a best size and shape for an avocado tree? Not universally. It all depends on the location and goals for the tree. An avocado tree can be healthy and productive at only eight feet tall and forty feet tall. An avocado tree can be healthy and productive shaped like a shrub, like the Japanese Fuerte, or like an upright Christmas tree.
However, there are some principles to keep in mind. The most important one is that lower and inner branches will become less fruitful and eventually die unless they get enough sunlight. This is why large avocado trees are like caverns, where the inside is nearly empty and most of the leaves and fruit form a dome.
This is a hundred-year-old avocado tree at The Huntington. Almost all of its live branches and fruit are up high or at the outer edge of its canopy.
If you want to keep your avocado tree smaller than it would naturally grow, then you’ll want to aim for something like a globe or fat pyramid shape where the upper foliage is narrower than the bottom so that it doesn’t shade the bottom foliage too much. See the shape of the Japanese Fuerte above and see my 15-foot Hass tree’s shape here.
This will ensure that the lower and interior parts of the tree remain fruitful. Here’s the inside of the Japanese Fuerte.
(For more on this, see my post “Pruning avocado trees to keep them small.”)
Making cuts and the tree’s response
Cutting back to a lateral branch is best, specifically a lateral branch that is at least a third as thick as the branch you’re cutting. If you do this, that lateral branch is likely to take over the growing energy of the branch you cut, and it’s also likely that your cut will heal well, maybe even close up its wound entirely. Here’s an example of such a cut and response:
But sometimes avocados, more often than other kinds of trees, decide to send energy into a lateral branch growing somewhat below your cut. Don’t be surprised or dismayed if this happens. An example:
Why not just trim an avocado tree like a hedge? You can do that, but be aware that, in the words of Ben Faber, farm advisor with the University of California, it “leads to an explosion of water sprouts that result from bud break up and down the branch because the terminal bud which control the buds lower down have been removed.” Cutting back to lateral branches leads to calmer regrowth.
Also, if done at the wrong time of year, giving the tree a buzz cut can leave you with little fruit the following year.
When to prune avocados?
When is the right time to prune avocado trees? The best time to prune avocado trees is late winter and early spring, especially if you’re cutting branches thicker than your finger.
The reasons are that from late winter we’re past the time when a serious cold snap can damage your tree (thereby “pruning” it further). Also, the tree is beginning to flower and grow new leaves, so as soon as you make your cuts the tree will begin filling in the gaps. Any branches that have been newly exposed to sun will likely be protected by foliage before the heat of summer threatens to sunburn them. (See my post, “Avocado trees get sunburned — what to do?”)
Furthermore, avocado trees create the buds that will produce flowers during summer. So if you prune by early spring, then the tree has the summer to create those flower buds. This way you’ll get maximum flowers and fruit the following spring.
What if you prune in summer? The new growth that comes out of the tree will not be mature enough to flower the following spring if you prune later than about early July.
Nipping back a little branch that is going in a direction that you don’t like is still fine during summer, however. In fact, it’s better to do this than wait until it is bigger and you have to make a bigger cut in late winter.
What if an avocado tree is 30 feet tall but you’d like to bring it down to 15? This is much more challenging than maintaining a tree at 15 feet tall, but it certainly can be done. In fact, it’s done all the time in commercial groves in California.
There are two ways to approach this. One is to “stump” the tree. This is drastic pruning where the tree is cut down to a stump of about five feet. All exposed bark must be painted. As the tree grows back over the next couple years, you then shape it and maintain it at your desired height. You’ll get no fruit for the first couple years.
I stumped this Sir-Prize avocado tree recently:
A less severe method involves cutting back one or two large limbs each year over the span of a few years until your tree has been brought down to the desired height. You still have to paint any exposed bark, which can be difficult since the painting sometimes needs to be done high up in the tree. But the advantage of doing this is that you won’t lose all of the tree’s fruiting capability.
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