Gadenin日本語Get the appBleeding is the whole problem
Cut a mulberry when the sap is moving and the wound will run with milky sap for days or weeks. The tree loses reserves, the wet wound is slow to seal and invites dieback, and a big cut made at the wrong moment can kill the branch behind it. This is not a minor blemish that stops on its own. It is the single reason mulberry pruning has its own calendar, quite different from apples and plums.
The sap starts moving well before you see any leaf, so waiting for buds to swell is already too late. Two windows are safe: deep dormancy in the coldest part of the year, when the tree is fully leafless and quiet, and late summer after the crop has finished but with enough warm weather left for the cuts to seal before autumn. Everything from bud swell through to midsummer is off limits.
| Timing | Safe to cut? | What happens |
|---|---|---|
| Deep winter dormancy, leafless and cold | Yes | Little or no bleeding; best time for structural cuts |
| Late winter as buds swell | No | Sap already rising; heavy bleeding |
| Spring and early summer | No | Worst bleeding; wounds stay wet and can die back |
| Late summer after the crop | Yes | Minor bleeding; cuts seal before autumn; good for small tidying |
| Autumn as leaves fall | Marginal | Wounds seal slowly going into cold and wet weather |
If a limb tears in a storm during the growing season, do not leave the ragged wound waiting for winter. Cut it back cleanly to a natural junction, accept the bleeding, and finish the tidying properly in the next dormant season.
How much to take, and where
Mulberries need far less pruning than most fruit trees. They fruit on both old wood and the current season's growth, so there is no shoot-by-shoot regime to follow and no risk of pruning the crop away by leaving the tree alone. Almost all the pruning worth doing is structural: taking out the four kinds of branch that cause trouble later.
Keep every cut as small as you can. Wounds under about two inches (5 cm) across close reliably on a mulberry; wounds over four inches (10 cm) often do not, and become the entry point for the decay that hollows old trees. Cutting a shoot the thickness of a pencil three years running is far better than removing a limb the thickness of your arm once.
- Dead, damaged and diseased wood Take it back to healthy wood at a natural junction. This is the only pruning that can be done at any time of year, and on a mulberry it is most of what an old tree needs.
- Crossing and rubbing branches Where two limbs touch, the bark wears through and rot follows. Remove the weaker or worse-placed of the pair while it is still small.
- Low branches over paths and paving Anything that will drop fruit where people walk or park. Lift the canopy gradually, a branch or two per winter, not all at once.
- Narrow, upright forks A tight V union with bark trapped inside it will split under a full crop. Remove one of the two stems while the fork is young, or shorten it so the other takes the lead.
- Congested growth in the center Thin enough that light and air reach the middle of the tree, but do not strip it out. Stop when you can see through the canopy in patches; over-thinning triggers a mass of water shoots.
Shaping a young tree
The first four or five winters decide what you will be living with for decades. Choose the clear trunk height early: a canopy that starts at head height, around six to seven feet (1.8 to 2.1 m), is far more usable than one that starts at three feet, because you can walk, mow and stand under it. Remove the lowest side branches one or two per dormant season, cutting them back to the trunk, until you have reached that height.
Then pick three to five well-spaced main limbs radiating in different directions with wide-angled unions, and let them go. Shorten anything competing with them and any shoot heading straight up through the middle. After that the tree is essentially built, and later work is limited to the four categories above.
Old, oversized and neglected trees
Mulberries live a long time and old ones become wide, low and heavy, with limbs sagging to the ground. They tolerate hard renovation surprisingly well, and even a severely cut-back tree usually breaks freely from old wood, but the work must be spread over three or four dormant seasons. Removing more than about a quarter of the canopy in one winter provokes a thicket of vertical water shoots and a great deal of bleeding from the large wounds.
Work to a plan: pick the worst limb each winter, take it back to a junction with a branch at least a third its diameter, and stop. Prop or shorten sagging limbs rather than removing them outright, since an old low branch is often the most productive and easiest part of the tree to pick. Never cut a mature mulberry back to bare stumps in one go.
Note what you cut
Write down which limb you removed each dormant season and roughly how thick it was, along with the height you have lifted the canopy to. On a tree pruned once a year over decades it is impossible to remember otherwise, and the note stops you taking two big limbs off the same side in consecutive years, which is how a tree ends up lopsided and unstable. Record any wound that is still weeping or has not closed a year later, and check it again the following winter.