A most amazingly frigid cold descended on my small kitchen garden yesterday. That’s actually helpful because the last week of February felt like spring, and I need a few more weeks of winter; I’m still pruning and grafting in my fruit trees.
If you’ve been following Your Small Kitchen Garden blog, I’ve been sharing with you thoughts about pruning apple trees… and most other deciduous trees. In the past two posts, we’ve laid the groundwork for pruning. In the first, we talked about reasons to prune your fruit trees, and offered some very broad guidelines. In the second post, we looked at pruning tools, and discussed the basic technique for cutting branches shorter or altogether removing them. This post offers describes what to prune and why.
A Pruning Operations Checklist
A branch in my pear tree snapped under the weight of fruit. The scar is a portal for disease and insects, so I’ll prune it away this winter. Notice the many healthy branches that are competing to take the place of the broken branch. I’ll prune most of those away as well.
Here, vaguely in order of priority, are the guidelines I follow when pruning apple trees… or peach trees or pear trees. These guidelines will work as well with all temperate climate deciduous trees:
1. If your tree is a chimera (root stock and fruiting stock grafted together), don’t prune off everything above the graft. Root stock may grow into a viable tree that even produces fruit, but not likely fruit you’d want to eat. So, if any branches emerge from the root stock (below the grafting scar), cut them off; undesirable root stock growth will compete with grafted stock.
You almost certainly won’t be able to identify the original graft on an older tree, but if the tree puts out young branches within a foot of the ground, they should go. Sadly, new, young branches sprouting low on the trunk of an old tree are a clue that the tree is unhealthy.
2. Prune all dead wood as closely as possible to live wood. If you find a live branch that has a lot of dead branches protruding from it, look for health issues with the live branch: Is the bark cracking? Is there obvious rot? Has the branch been bent severely? Are there holes in the bark? If there are a lot of dead branches on a live branch, the live branch is probably dying. You don’t need to remove it (yet), but do so if removing it fits easily with the rest of your pruning plan.
3. Prune away branches that have splits, cracks through the bark, peeling bark, or obvious rot. Fungus is a sign that a branch is only partly alive—but a healthy branch may have algae, moss, and even lichens growing on it.
Three branches of about the same diameter run nearly parallel. Branches that emerge from these intertwine, competing for sunshine. If these branches all emerge from the same “parent” branch, it makes sense to remove two of them. If they emerge from separate parents, removing competing sub-branches and shortening one or two of the larger branches shown may be the better choice.
4. Prune to rid trees of branches that touch each other—or that are growing into the same space as other branches. Touching branches rub in the wind, making holes in the bark. They might also trap water that promotes rot and attracts insects. Branches growing into the same space compete for sunlight. Generally, preserve the healthier branch, and remove the weaker one.
5. Don’t make one branch do the work of several. It’s an easy mistake to make: You find three or four main branches whose lesser branches grow into the same space. Removing all but one of the main branches would simplify the tree. However, it would be better to preserve the main branches and prune lesser branches from them. This encourages new growth from the main branches, and might produce lesser branches to fill the tree out in other directions.
6. Prune branches from above to let light onto the branches below… and to let light into the middle of the tree. A tree north of the equator may need more severe pruning of its southern branches as those shade lower branches on the north side of the tree. My apple trees are on a north-facing hill, so the lower, northern branches see little sunlight. While the trees grow generally up, newer growth tends to lean southward, and those low, northern branches curve around the rest of the tree.
Here’s my best apple tree with a six-foot step ladder for scale. The tree is out of control; I’ll never be able to reach apples in those crazy high branches. Notice that the tree seems to reach out over the stepladder with only low branches on the opposite side of the trunk. Yes: the stepladder is on the south side of the tree. New growth follows the sun, particularly when you don’t prune each season.
7. Prune off branches that offend your sense of aesthetics or practicality. What do I mean? Aesthetics: does the tree suite your eye? Does it fit into your small kitchen garden’s landscape? Does it block a view you wish you had? Practicality: I hate ducking under branches when I mow the lawn; I don’t want my fruit trees to branch in the first six feet of trunk. You may not care about ducking, but does the tree block a window or shade a planting bed? Once you’ve taken care of the big problems (which may require a season or two of pruning), move on to shaping the trees so they make sense to you.
8. Don’t cut really thick branches if you can avoid it, and especially resist cutting the tree’s leader. A big scar stresses the tree and makes it more susceptible to disease. Cutting large branches may start the tree into decline.
9. Don’t paint pruning cuts with sealant or paint. These may prevent the tree from healing properly.
10. Don’t prune within one-year-old growth. The last few inches of a tree’s branches are the previous season’s delicate growth. Cut off some of it, and the rest might dry out and die. To shorten a branch, cut farther down the branch in the 2nd or 3rd year’s section. If there are spurs sticking out from the branch beyond the pruning point, you’re cutting within older growth.
Especially when you’re recovering an old, neglected tree, all of these guidelines come into play. But guideline number 8 will give you the greatest challenge. Three of the five fruit trees that came with our house were simply too messy; I cut several large branches to limit their height and encourage spreading and enlarging of the lower branches.
I did the most severe pruning in a tree I didn’t like. My thinking? If I kill it, I have one more excuse to cut it down. In that tree, I cut out the leader and several side branches that had grown as thick as the leader and ran parallel to it. These were five- and six-inch diameter trunks.
Most of the large cuts I made have healed well. However, the most severe cut didn’t heal, and the wood is rotting a hole into the tree. The tree isn’t in great health, and I expect it won’t outlive me (knock wood)… though I’m trying to engineer it for longer life.
If you’re going to cut such large branches:
1. Cut side branches close to the tree’s trunk with the saw blade running parallel to the trunk.
2. Cut the leader just above several healthy branches that can compete to replace the leader once it’s gone.
3. When cutting a vertical branch—particularly a very thick one, cut at a bias so you don’t leave a horizontal surface; water should run easily off of the newly-exposed wood.
It’s best to shape a tree when it’s young and keep it under control so you never have to cut branches more than an inch or two in diameter.