Care and maintenance · Bonsai
The bonsai year: what to do and when
Almost everything that kills a bonsai is the right operation done at the wrong time of year. Repotting in August, hard pruning in autumn, wiring a tree that is already struggling — each is fine in its season and damaging outside it. This is the calendar, and the single most important entry on it is the one that says do nothing.
A bonsai is a tree kept small by repeated intervention, and every intervention costs the tree something. It recovers by growing, and it can only grow when its season allows. That is the whole logic of the bonsai year: work is scheduled for the moments when the tree has the resources to repair itself, and withheld when it does not.
This is why generic advice kills trees. The instruction "repot every two years" is useless without the season, and the season differs by species — a larch, a juniper and a ficus do not share a calendar. What follows is the shape of a temperate outdoor year in Britain, and the species-specific timings should come from a source that knows your tree.
- Late winter, before buds move — The repotting window for most deciduous species, and the only time root work is reasonably safe. The tree is dormant, the roots are about to grow, and it will spend spring repairing what you did. Structural pruning also happens here on deciduous trees, when the branch structure is visible without leaves.
- Spring, as growth starts — Feeding begins. Watering demand climbs quickly and this is where beginners under-water — a tree in leaf in a small pot dries far faster than one dormant. Do not repot once buds have opened; the moment has passed.
- Late spring to early summer — Pinching and directional pruning to build ramification while the tree is growing strongly enough to respond. Wiring is reasonable here on most species, and this is the season with the widest margin for error.
- High summer — Mostly watering and shade management. Heavy work now competes with heat stress, and a tree cannot both recover from pruning and survive a hot fortnight in a shallow pot. This is the season to leave trees alone.
- Autumn — Feeding tapers. Remove wire before it bites as trunks thicken in the last growth push. Avoid hard pruning: the tree is withdrawing resources rather than building them, and it has no season left to repair in.
- Winter — Protection rather than work. Most temperate species need their cold period and should not be brought indoors, but roots in a shallow pot freeze far harder than roots in the ground — which is the actual risk. Shelter the pot, not the tree.
- Two major operations in one year — Repotting and hard pruning in the same season asks a tree to rebuild roots and canopy simultaneously. Pick one, and give the tree a year.
- Bringing an outdoor species indoors for winter — The commonest way a beginner kills a juniper. Temperate species need dormancy; a warm windowsill denies it. Indoor bonsai is a separate category of species, not a separate location for the same ones.
- Wiring a weak tree — Wire restricts and stresses. A tree that is recovering, recently repotted or in poor health should be left to grow first — styling can wait a year, and a dead tree cannot be styled at all.
- Following a calendar written for a different climate — Most bonsai material online is written for continental or Japanese conditions. British winters are milder and wetter, which shifts timings and makes root rot a bigger risk than freezing.
Questions this guide answers
Listed so you can tell at a glance whether this is the page you wanted. HobbyHQ keeps one guide per question family rather than a page per phrasing.
- when should I repot a bonsai
- when to prune bonsai
- bonsai care calendar
- what to do with bonsai in winter
- when to wire a bonsai
- bonsai seasonal care
Part of Bonsai. Last reviewed 2026-08-15.