Our bonsai break bud at different times. When is best to repot? Do we repot them all at once?
The general guideline to repot as they break bud is a good one. Some, like pines, though, are repotted a bit before we see bud elongation. Maples, as buds open.
If you have a long spring—one that goes on at a mild temperature for a couple months or more—then the schedule separates into phases.
A long spring schedule may look like this:
- Deciduous first: Quince (Japanese and Chinese), Trident
- Then, Black Pines
- Satsuki, as they green up
- Single flush pines, like Japanese White and Ponderosa
- Spruce
- Then more deciduous, like Japanese Maples, Elm
- Hinoki
- Beech, Hemlock
- And finally, Juniper
If your spring is short, just a month, trees may be repotted roughly at the same time.
Bud swell on Hemlock, about right repotting timing
Ponderosa Pine—a bit late
Black Pine—much too late
Ezo Spruce—the tree on the right, correct repotting timing; tree on the left, too late. Tricky for this one as it’s a forest…try to repot earlier in this case, gauge by the first tree to begin moving.
Beech—a hair early. Beech are tricky. They are late openers, usually almost overnight. Ideally, wait for a bit of green between the bud scales to show, then repot.
Vine Maple—like many maples, they can be repotted a bit “long in the tooth”, when the buds are swelling and opening
Though Maple can be repotted with buds opening, once leaves are out it’s on the late side
If repotted outside an ideal window—before or well after bud break—place tree in shelter, preferably a greenhouse for several weeks. Greenhousing a plant is good practice after normal repotting for protection from wind, frost and too much rain, but outside the repotting window it can be critical tool for success.