Your tree is alive! (for now...)
Something called apical dominance will guide you to successful fruit tree pruning. But you'll have to learn to read your tree.
I don't like bring bad news, but I’ll wager that up until now you’ve been going about pruning all wrong. Don’t blame yourself—they don’t teach this stuff in school.
Well, I suppose they teach it in Horticulture School, but you probably didn’t go there. I didn’t go there either.
I made the same mistakes as you when I was getting started. It’s frustrating, because if we keep doing what we were doing, we’re likely to weaken and eventually stunt or even kill our trees.
A couple of years after I planted our apple trees, I realized they needed some pruning. Well, to my credit, I did do a little research ahead of time. I figured out how to make a decent thinning cut, but that was about it.
I knew I wanted to open up the tree to air and light, but beyond that, I had no idea what I was doing. I made my cuts, and the trees didn’t die. Success, right?
Then I came back the next year, and instead of feeling more confident this time, I felt more uneasy. Before, I could blithely make the cuts, knowing I was making them “properly”. But this time, I knew I was missing something. Something huge.
But I didn’t know what. So I made my cuts, and again, the trees didn’t die.
When I came back the third year, and I knew I couldn’t go on like that. I knew how to make a pruning cut, but I had no idea why I was making each cut, outside of the vague goal of “make the tree smaller”. So I went to the library.
I love libraries.
This is what I learned.
The real reason you’re not succeeding in your pruning can be summed up in two words: apical (APE-ickle) dominance. “Say what?” you might say. I say “exactly.”
If you understand those two words, and learn how to use them, you will be the pruning master, and I will have taught you everything you need to know. We’ll start with this:
Your tree is not dead.
Your tree is alive.
I’ll say it one more time: your tree is alive!
It’s easy to get fooled by a tree. Everything they do takes a long time. You make a pruning cut today, that tree may take a year to get back to you about how it feels about it. But oh! it will have an opinion.
Don’t worry, I’m not about to advise you to hug the tree and ask it about its feelings.
Instead, we’re going to talk about buds.
Buds are where all the exciting tree things happen. Apples on your apple tree? They start as buds. Leaves? Buds. New growth? Buds.
There’s a lot to know about buds. We’ll start with the most important bud, as far as it goes for pruning and training your tree: the terminal bud, in some cases called the apex bud or the “boss” bud.
You can easily identify a terminal bud. It’s the end-of-the-line terminal, at the very tip of the past year’s woody growth. You’ll see the buds form at the end of the main growing season as the tree prepares to go into dormancy. Depending on the kind of tree we’re talking about, the terminal bud may be a fruiting bud or a vegetative bud. We’ll go into those differences later.
Now, why get excited about terminal buds? Because of apical dominance of course! (“Say what?!”)
When a terminal bud is higher than other buds, we call it an “apex” bud. Apex. Apical. Tip-top.
The thing to know about apex buds is that they produce a plant hormone called auxin. This hormone flows downhill through the branch. When the hormone reaches other vegetative buds (called “lateral buds”), it gives them a signal: “Orders from the top. Sit tight. Don’t steal the show. I’ve got this growth thing covered.”
That’s why they call the apex bud the “boss bud”. It gives orders to the other buds.
You could say that the apex bud dominates the other buds. Apical dominance. Fancy phrase for a simple idea.
But get this:
When you prune a tree, you are upsetting the chain of command.
When you cut into a branch, you are cutting off the flow of hormones from the boss bud.
When you train a branch, you are slowing the flow of hormones from the boss bud.
When lateral buds don’t receive orders from the boss bud, they know it’s their time to shine. And when the growing season starts, they get to growing.
When you understand apical dominance, you don’t need to ask the tree about its feelings. Instead, you can predict how the tree will respond to each cut. You can plan your cuts strategically to produce the shape of tree that you want. (Don’t worry: we’ll go deeper into that in future articles!)
Understand apical dominance, and you will become a pruning master.
We’ll talk more about this, and especially about buds. Until then, though, here’s your assignment.
Your assignment: go on Google Image Search and look up “apple tree terminal bud” (or whatever kind of tree you have), and get familiar with what they look like.
If it’s late fall or winter, go out to look at your tree and look for the buds. Try and find the terminal buds.
If it’s some other time of year, go out and look at your tree anyway. It misses you.