The Japanese maple (Acer palmatum) is a very varied species of maple. Numerous cultivars have emerged from it over the centuries, especially because this tree species is very popular for bonsai cultivation in its Japanese homeland. Red Japanese maple is particularly interesting for this purpose, as it offers a distinctive look all year round thanks to its striking foliage color.
How do you care for a Japanese maple bonsai?
A Japanese maple bonsai needs a bright, wind-protected location, regular watering without waterlogging and monthly liquid fertilizer. Pruning takes place in May and June, wiring in June. In winter, frost protection or frost-free wintering is required. Watch out for verticillium wilt and choose an appropriate variety.
Location
Fan maple requires a location that is as bright as possible and, above all, protected from the wind, but which does not offer sun all day long. Most varieties are content with morning and afternoon sunlight, but prefer to be in light shade in midsummer and at midday. In strong radiation, the leaves can wither due to sunburn, and leaf tip drought can also occur as a result of drafts.
Watering and fertilizing
When it comes to water requirements, the Japanese maple is a bit complicated: it likes it moist and should not dry out if possible - but the tree doesn't like being too moist either. The exotic does not tolerate waterlogging at all, which is why you should also ensure good drainage. Fertilize approximately every three to four weeks with a liquid fertilizer (€4.00 on Amazon), although you should first reduce the doses - at least when overwintering outdoors - until around the beginning / middle of August and then stop them.
Cutting and wiring
In contrast to other types of maple, the Japanese maple is generally more pruning-tolerant, but should only be pruned in the months of May and June and should always be treated with a wound closure agent (preferably tree wax). For finer branching and smaller leaves, the shoot tips are cut back after sprouting. Wiring takes place in June, although the wire should be removed after six months at the latest.
Wintering
The Japanese maple is actually a hardy tree species that is used to long and snowy winters in its Japanese homeland. However, since the bonsai plant grows in shallow bowls, its roots can quickly be damaged by frost. For this reason, Japanese maple should only be left outside with good winter protection or hibernate frost-free at a maximum of six degrees Celsius.
Diseases and other disorders
Like all maples, the Japanese maple is very susceptible to verticillium wilt caused by fungi, in which the leaves and then the shoots suddenly and seemingly for no reason dry up. There is currently no effective remedy against this disease; in most cases, the painstakingly nurtured tree is doomed to die. Only repotting in fresh substrate and drastic pruning can sometimes save the day.
Suitable varieties
Traditionally, the following varieties of Japanese maple are trained for bonsai:
| Variety | Growth | Annual growth | Leaves | Autumn Coloring | Special features |
|---|---|---|---|---|---|
| Atropurpureum | tree-like, sprawling | 30 to 50 cm | dark red | bright red | intense color |
| Beni komachi | upright | 5 to 10 cm | purple to salmon red | bright red | wavy leaf edges |
| Katsura | upright | 5 to 7 cm | light green | bright orange | dwarf, small leaves |
| Murasaki kiyohime | wide-growing | 5 to 6 cm | light green with red border | yellow | dwarf |
| Kotohime | columnar | 5 to 10 cm | green | bright yellow | small leaves |
| Orange Dream | upright | 5 to 10 cm | yellowgreen | yellow-orange | good branching |
| Osakazuki | upright, shrub-like | 10 to 15 cm | freshgreen | bright red | beautiful blossom |
| Shaina | thickly bushy | 5 to 10 cm | bright red | orange | cut compatible |
Tip
Until it is around 10 years old, Japanese maple is repotted every two years, then every five years.