The other day I had a good time giving a talk about growing citrus to the Lake San Marcos Garden Club, and a couple of people asked me about pruning. My impression is that most of us think that, as a general rule, all fruit trees need to be pruned. It’s simply not true, especially regarding citrus. In contrast to this mistaken notion I’d say that, as a general rule, citrus should not be pruned. I can think of only a couple of exceptions to this rule.
In my yard I grow eight citrus trees, and out of those eight I only ever touch two with my pruners, each for a different reason.
PRUNE TO KEEP A CITRUS TREE SMALL
I give our Bearss lime tree haircuts because I want it to stay small, to about the height of my three year-old son. It already produces more limes than we use at that diminutive size. Once a year I prune it by just trimming off every branch that is taller than I want, or by handing Cass the pruners.
Five year-old lime tree being pruned by a three year-old boy.
PRUNE TO SHAPE A CITRUS TREE
I also prune our large Valencia orange tree. It’s 25 feet tall, and I’ve never tried to trim the top. Rather, I prune the sides and interior to create an umbrella shape. I keep its skirt a few feet off the ground and then I keep the inside pruned high enough that we can walk around under it so that it feels like an outdoor living room. I prune up a couple of spots on its canopy edge to make doorways for entrance. Shaping this citrus tree in this way makes it a very comfortable spot to sit in the shade on a summer day.
I’ve even hung a swing from one of its branches.
Keeping a tree small like my lime and shaping a tree like my Valencia are the only two good reasons I can think of for pruning citrus. There are plenty of bad reasons though.
DON’T LACE A CITRUS TREE
The worst reason, or way, to prune a citrus tree that I’ve encountered is opening up the tree’s canopy so the interior gets sunlight. That can be a good idea for some other types of fruit trees, like plums and peaches. It’s definitely not advisable for citrus, however.
Why not? I once did a home consultation at a multi-million dollar residence in Rancho Santa Fe where the owners had put in an orchard of a few dozen fruit trees and then their hired gardener had pruned all of the citrus trees just like the peaches and plums. The foliage had been thinned, entire branches had been cut out, the canopies had a skeletal look, and the effect was that you could see lots of light going through the trees and hitting the interior branches.
Why are our citrus trees dying? the owner asked me. All of those interior branches now exposed to the sun were cracking and blackened from sunburn. Yes indeed, trees get sunburned.
If you want to keep a citrus tree small or shape it, then trim the outside like you would trim a hedge. Don’t cut out entire branches and expose interior parts of the tree that are used to being shaded. Have a look at this video showing how citrus farmers mechanically prune their trees. This farm is in Spain, but the same technique is used here in Southern California, and the world over.
A citrus expert once told me that if a citrus tree is in prime health, then if you look at its canopy you won’t be able to see any light or sky through it. It should be a dense green globe.
A couple of other no-good reasons to prune citrus include cutting out dead or crossing branches. That’s just a big old waste of your time. Do it if you have nothing better to do, but your citrus tree couldn’t care less if some of its branches are crossing or are dead and hanging. Both are harmless and natural. I don’t cut out any dead or crossing branches on my citrus trees and they’ve never complained about it.
Also, if aphids or leafminers or other insects have damaged the leaves of your citrus tree, don’t waste your time cutting those damaged leaves out. They’re still capable of photosynthesizing and contributing to the growth and fruitfulness of the tree even though they’re not completely healthy. Pruning them out won’t make a significant difference to the insect population in the tree either. Better to adjust your aesthetic sensibility than cut up the tree, in terms of the health of the tree.
Lastly, and here’s a bit of a twist, do pay attention to what’s growing from low down on the trunk of your citrus tree. I don’t think of this as pruning, but it’s really important that if any branch starts growing from below the graft (bud) union of your citrus tree you immediately remove it. If you’re unsure of what I mean by that, then please read my post titled, “Beware of rootstock suckers on citrus.” It might save the life of your tree.
Isn’t it a relief, though, to know that your citrus tree knows how to grow pretty well on its own? That’s why you can find citrus trees thriving even in Southern California yards that have been neglected for years. And that’s why every Southern California yard should have a citrus tree, or eight.
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Opinions on how to prune deciduous fruit trees are innumerable. I have just one: Keep your tree small.
I believe it’s the single best thing you can do if you want your tree to produce fruit and you want to pick and eat that fruit.
A small tree’s fruit is easy to pick. In fact, by “small” I mean within reach, which is different for everyone but is usually six to ten feet tall. The fruit on such a tree is in your face — you just reach out and grab it. Some of the fruit on my trees are even low enough to be in the face of my two-year old son, so he also just reaches out and grabs it. (That’s good and bad. He has a hard time not grabbing it before it’s ripe.)
But if you let a tree get tall, then the fruit is borne primarily high up, out of reach. Trees generally fruit most in the part of their canopy that gets the most sunlight, and that’s toward the outer and upper part of their canopy. I once had a plum that was 15 feet tall, and while a bit of the fruit was within reach, most of it was out of sight and only accessible by ladder or pole, or squirrels and birds. In the end, most of that fruit was lost to the critters. My current plum is seven feet tall and I have never lost a single piece of fruit to animals, and despite its smaller size it is still big enough to produce more fruit than we can eat.
A small tree can be protected if necessary. My aunt has a small peach tree which she easily covered with a net once the birds discovered her fruit and started pecking it this last summer. Try covering a 15-foot tall peach with a net!
Yet I haven’t even found the need to net my own small trees. My Blenheim apricots attract scrub jays as soon as the fruit begins to sweeten. The birds peck some of the ripe fruit but don’t ruin it. That fruit is at head height on my tree, so I immediately notice it and pick it. I take their peckings as a sign of ripeness. “Eat this fruit, Greg. It’s ready.” There’s still so much more fruit on that little tree that the birds never touch.
I don’t like the idea of telling you how you should grow your fruit trees. Truly, do whatever you want. But after having many trees both big and small, I’ve found that small is better. I’m in good company, by the way. I don’t know of many people with a lot of experience with deciduous fruit trees who let their own trees get big anymore.
So, how to achieve this goal of a small tree? The topic of pruning can be studied for a lifetime, but the achievement of a small and productive fruit tree can be had with very little knowledge and little work. For each one of my trees, I prune them once in the winter (just finished my pruning yesterday) and once or twice in the summer. The total time involved is around an hour per year per tree.
What do you need to know in order to do the pruning? Tough question because obviously the more you know the better your pruning is likely to be. On the other hand, you could literally shear your fruit tree as though it were a shrub and still get decent results. Shearing a fruit tree is actually a thing, the “fruit bush” style it is called sometimes. Try it, or dive deeper into the resources below, which are the best ones I know of.
The Home Orchard published by the University of California (this is an Amazon link, but your local library might have it too — I borrowed this book from the library many times before I bought my own copy)
Chuck Ingels, a University of California Cooperative Extension Farm Advisor, presents on growing deciduous fruit trees to a group of Master Gardeners in this video called “The Home Orchard Part 1.” The pruning section starts at 36 minutes. This video is great because Ingels explains things clearly, shows many photos that illustrate his points, and relates his own experiences in his own yard. He talks about the “fruit bush” style just after 52 minutes. Also, continue into “The Home Orchard Part 2.”
Tom Spellman of Dave Wilson Nursery prunes fruit trees plus gives some of his reasoning in this video titled “Winter Pruning.” Perhaps the best thing about this video is that you can watch Spellman make the cuts; then you can go out to your tree and imitate if you like. I’m sure you’ll find it useful to watch some of the many other videos Spellman has done on pruning too.
Fruit Trees: Training and Pruning Deciduous Trees by Chuck Ingels (again), Pam Geisel, and Carolyn Unruh. The information is dense, but it’s all there, and it’s freely available as a pdf. It’s kind of like the condensed version of the book The Home Orchard.
How can the un-local Davis Garden Show be the best one for Southern California? It’s partly that the radio show/podcast is that good, and it’s partly that co-host Don Shor grew up in La Jolla and knows about growing plants here better than we do and kindly remembers to make side notes about how gardening works in our slightly drier and milder neck of the woods.
Last week’s episode perfectly represents why the Davis Garden Show is the best. In this January 5, 2017 episode, Shor talked all about the timely topic of deciduous fruit trees, from bare root planting, to training and pruning, to the meanings of terms like “sucker” and “pollenizer.”
The episode is so packed with information that you’ll want to listen multiple times. Shor articulates the concepts so well that even if they’re not new for you, you’ll enjoy listening to him describe them. But he isn’t reading from a horticulture book. Shor has studied horticulture formally at U.C. Davis, but he has also run a retail nursery, Redwood Barn Nursery, for decades, and he grows just about everything on his large property in the Davis area. When he says he recommends training most fruit trees to a “modified central leader” structure, it’s because he has trained many trees in other styles over the years, and he gives reasons and examples to support why modified central leader is his favorite for backyard growers. (The photo above shows Fuyu persimmon trees that have a modified central leader structure.)
In other words, when you listen to the Davis Garden Show you get not only an education but also ideas that are concrete and with which you can take action.
The Davis Garden Show broadcasts every Thursday at noon, when Shor is usually joined by co-host Lois Richter. You can listen to the show live from the KDRT website, but I always stream or download the podcasts on my computer or phone, which you can do from here or here.
Listen to the January 5, 2017 episode, and also listen to the excellent previous episode about fruit trees from December 29, 2016. From there you’ll probably be hooked like me, and you can browse past episodes for topics of interest, and you can listen to the latest episode for timely topics.
This young Cara Cara navel orange tree looks fine, right? That’s what I thought until I crouched down and noticed this little devil:
That branch growing from the base of the trunk — that’s the little devil. It’s not a branch of Cara Cara navel orange; it’s rootstock.
Almost every citrus tree you can buy from a nursery (the main exception being Meyer lemon) is actually two trees in one. There is a rootstock on the bottom, and there is a scion on top. The scion is the part that gives you the fruit you desire.
Usually you can spot the union where the rootstock and scion were grafted together because the bark has a change in shape there, sometimes an extreme bump but sometimes only a subtle line. Can you see the graft union on my tree above? It’s just below where the branches start. It looks a bit like a “V”.
Beware. If the rootstock on a citrus tree sends up a branch, often referred to as a sucker, it will be vigorous and it will eventually take over the whole tree. Within a couple years, you’ll find that all of your tree’s fruit taste sour, and that’s because it’s not really your tree’s fruit — it’s not the scion’s fruit, that is. It’s rootstock fruit.
So keep an eye out, and cut any rootstock suckers off immediately.