Maples come in a variety of sub-species, but all of them make beautiful bonsai trees. Slightly more difficult to care for, they are nonetheless greatly in demand by bonsai enthusiasts. Their leafy appearance is attractive, particularly in the fall when they turn to yellow and red, just as do the full-sized maples.
Some varieties thrive well as indoor plants, but for the most part bonsai trees are outdoor plants. Opinions vary about how much sun they require, but partial sun/partial shade is a safe bet with most types.
They survive winter well in the wild, but in bonsai form they require some care. Less water in the winter is called for and care should be taken that the roots don’t get any frost.
Copious watering in the summer is warranted, provided – as with any bonsai tree – there is good drainage. A little extra moisture isn’t a bad thing, though, especially for the flowering varieties. Maples like moist soil.
They adapt well to various styles, but the informal upright (shakan) may be best, given their leafy nature and somewhat brittle branches. It is possible to train them into the han-kengai (semi-cascade) and others, but extreme care must be taken to avoid splitting the trunk and branches.
Han-kengai can be achieved without wiring by a cord attached to a stake in order to curve the trunk. However, this form doesn’t typically occur in nature. Since traditional bonsai art aims at emulating nature on a small scale, this form is uncommon.
Feeding once per month is fine, with a slow-release fertilizer from spring to autumn. Taper off during hot summer months, though. An organic type works well, but Peter’s 20-20-20 is also a good mix. Hold off any feeding for a few weeks after repotting.
Since they can produce ample branches and leaves, root systems tend to grow accordingly to support them. Pruning, therefore, should be taken as a concerted project. For fewer branches and leaves, roots can be pruned more aggressively.
Branch pruning is best carried out in fall or winter when there are fewer or no leaves. This gives a clearly visible working area, leading to fewer mishaps. Maples heal better if pruning paste is used to seal the wound after branch removal.
Pinch back new growth during the active growing season to keep foliage to a moderate level. Remember you are creating a bonsai, where the goal is somewhat minimalist. A fully leaved tree looks more like an ordinary houseplant.
Wiring is less common with maples for a variety of reasons beyond the somewhat brittle branches. They acquire pleasing shapes with leaf and branch pruning without extra effort and they scar easily.
Like most bonsai trees, repotting every two years is a good practice. When replanting a mixture of 60% soil, 20% peat and 20% coarse sand will provide the correct drainage environment. This is best done in early spring, before buds have started.