Gadenin日本語Get the appWhy the usual citrus timing does not work here
Most citrus is pruned in late winter, once hard freezes are past and before the spring flush breaks. An amanatsu, a large sour orange that hangs its crop from winter deep into spring, is carrying a full load of fruit at exactly that moment. Prune then and you are cutting off fruit you have already waited eight months for, and working on a tree whose reserves are fully committed.
So the window moves. Prune immediately after you clear the tree, in spring, and get it done before the new flush has extended and hardened. That gap is short, often only two or three weeks, which is why the job needs planning rather than improvising on a free weekend. Have the tools sharp and the plan decided before you pick the last fruit.
The compensation for the tight window is that you are pruning a tree you can read clearly. You have just handled every fruit, so you know which branches cropped well, which ones held fruit that never sweetened in the shade, and which ones bent under the weight all winter. That is far better information than you get from looking at a bare dormant tree.
Prune for light and for weight
Amanatsu is a large, vigorous tree, and it holds heavy fruit for a long time. Two goals follow. The first is light: interior fruit that sits in shade for eight months ripens unevenly, keeps its acid longer and is the hardest to inspect for rot through winter. Opening the center so light reaches into the canopy improves the crop everywhere inside it. The second is weight-bearing: every fruit you leave will hang through winter storms, so weak, narrow-angled and overextended wood has to go now rather than break under the weight in a winter storm.
Keep the overall approach light. Citrus does not want the hard renewal pruning that an apple or a plum tolerates, and stripping the canopy exposes bark that has never seen direct sun. Sunburnt bark on a limb splits and lets in rot. As a rule, take no more than about a fifth of the canopy in any one year, and if the tree needs more than that, spread the work over two or three seasons.
Cut back to a branch junction or to the branch collar, not to a random point in the middle of a limb. Stubs die back and become entry points, while a cut just outside the collar seals over cleanly. Do not paint wounds with sealant; on citrus it traps moisture behind it and does more harm than the open cut.
| What you are looking at | Cut or keep | Why |
|---|---|---|
| Dead, cracked or clearly diseased wood | Cut, back to live tissue | It will not recover and it harbors rot and scale |
| Branches crossing and rubbing | Cut the weaker of the two | A rub wound opens the bark and scars fruit all winter |
| Vertical water shoots in the center | Cut at the base | They shade the interior and never carry good fruit |
| Suckers below the graft union | Rub off as soon as seen | They are rootstock and will overrun the variety |
| Thin twigs that bent under fruit | Cut back to stronger wood | They cannot hold an amanatsu through winter wind |
| Low branches sweeping the mulch | Cut back or up | Fruit touching soil rots and invites ants and scale |
| Healthy outward-facing lateral wood | Keep | This is where next winter's crop will hang |
Working through the tree
Do it in a fixed order and you will not over-cut. Every one of these steps is a decision you can make from the ground with the tree in front of you, and the sequence puts the cuts you cannot regret first.
- Clear the tree first Finish harvest completely before you start. Pruning around hanging fruit means knocking fruit off, working awkwardly, and leaving cuts you cannot see properly.
- Sharpen and clean the tools Use sharp pruners for wood up to about half an inch (12 mm) and a pruning saw above that. Wipe the blades with alcohol between trees, and again after cutting anything diseased. A crushed cut heals slowly and lets rot in.
- Take the dead and the damaged Remove everything dead, cracked or broken, cutting back to clean live wood. Do this first; it costs the tree nothing and often reveals that less further work is needed than you thought.
- Remove crossing and inward growth Where two branches rub, take the weaker one. Then remove branches growing back into the center. This is what opens the canopy to light and air.
- Cut out the water shoots Remove the strong vertical shoots rising from the interior at their base. They shade everything below them, they rarely bear well, and they steal vigor from wood that does.
- Deal with the low skirt Lift the lowest branches clear of the mulch by around a foot (30 cm). Fruit resting on damp ground rots, and a skirt on the soil is the highway ants use to farm scale up into the canopy.
- Shorten the overextended Cut back long, whippy branches to a strong outward-facing side branch. You are shortening the lever arm so it can hold fruit through eight months of weather.
- Stop and look Step back before every further cut once the obvious work is done. If you have taken about a fifth of the canopy, stop for this year regardless of what else you can see.
What not to cut, and when not to cut at all
Do not prune in autumn or early winter. Cuts made then are open wounds going into the cold, and any regrowth they trigger will be soft, tender tissue on a tree that has to shelter a full crop for months. Autumn pruning is the most common way home growers lose an amanatsu crop to frost damage.
Do not cut out cold-damaged wood in winter either, however dead it looks. Wait until growth has restarted in spring and the live tissue is visible, then cut back to it. Wood that appears finished while the tree is still dormant very often pushes new shoots a few weeks after growth restarts, and cutting early almost always removes branches that would have recovered.
Do not shear the outside of the tree into a shape. Hedge-cutting citrus produces a dense outer shell of twiggy growth and a dark, dead interior, which on a long-hanging fruit is exactly the wrong structure. Every cut should be a decision about a specific branch.
Finally, do not treat pruning as a substitute for thinning. Removing wood does not reduce the load on the tree in the way that removing fruit does, and an unthinned amanatsu will swing into alternate bearing no matter how neatly it is shaped.
If a limb has to come off a mature tree, use three cuts: an undercut a foot out from the trunk, a top cut a little further out to drop the weight, then a final cut just outside the branch collar. A single cut tears bark down the trunk as the limb falls, and that wound takes years to close.
Note what you cut and where the good fruit was
Write down the date you pruned, roughly how much you removed as a fraction of the canopy, and any large limb you took off. Then add the thing you will otherwise forget: which parts of the tree produced the fruit that actually sweetened properly, and which parts held fruit that was still sour when you cleared it.
That last note is what turns pruning from tidying into a decision. Over two or three years it shows you exactly which zones of your tree get enough light for the acid to fall on schedule, and you prune to enlarge those zones instead of guessing at a shape.