Trees for bonsai (Japanese maple and sweetgum)

Japanese maple (Lat. Acer palmatum)

This maple is very popular in gardening for the shape and color of its leaves and the beauty of its canopy. Japanese maple is a small tree or shrub, growing to a maximum of 10 meters. Breeders have developed hundreds of Japanese maple varieties with different leaves and growth habits. It grows fairly slowly. Japanese maple is one of the most popular plants among bonsai enthusiasts. This is probably because it has beautiful small leaves that suit the proportions of a miniature tree, and in autumn those leaves take on gorgeous colors. The main difficulty in caring for Japanese maple is its delicate leaves, which are easily damaged by direct sun and strong wind.

Bonsai styles for maple: all styles except Bunjingi (文人木) and Hokidachi (箒立ち) Article on bonsai styles Placement: In early spring, good light makes the leaves stronger. In summer, though, the tree should be placed where direct sun can’t reach it. It must also be kept out of strong wind. It only needs winter protection if the temperature drops to -10 degrees or lower.

Watering: Water regularly but moderately; the soil in the pot should be moist, not waterlogged. Excess moisture can cause root rot. Fertilizer: Start feeding in early spring, when the buds begin to open, once every 2 weeks. At this stage the fertilizer should be high in nitrogen, which encourages healthy leaf development. Some specialists believe that in early spring you should feed once a week. For the rest of the season, use a balanced fertilizer. Stop feeding in autumn, when leaf fall begins. Repotting: Repot a young tree (under 10 years old) every year or every 2 years if it is growing in a small pot. Repot older maples once every 3–4 years. Repotting is done in early spring. Prune back only a third of the roots. Be sure to cut away all damaged roots.

Pruning: Thick branches are cut in late autumn. Always treat the cut with cut paste. If strong new growth is needed for styling, shorten the branch or shoot during dormancy so that only 1 or 2 pairs of buds remain. If we want short internodes and weak shoot growth, then during the growing season shorten each new shoot back to 2 pairs of leaves once 3–4 pairs have appeared. Remove newly emerging buds that aren’t needed. Full defoliation is done from the end of May to mid-June, every other year. Do not defoliate a sick tree, or in the year it was repotted. Besides reducing leaf size, defoliation makes the tree grow stronger, more attractive leaves. Wiring: Wiring is done from early spring to late autumn. Because the branches are fairly hard, maple is shaped mainly by pruning, but wire can be used when necessary.

Sweetgum (Lat. Liquidambar)

A deciduous tree with broad leaves. It can grow up to 25 meters tall. Native to eastern North America and Mexico. It is especially striking in autumn thanks to the varied colors of its leaves. Bonsai styles for sweetgum: all styles except Bunjingi (文人木) Placement: Keep it in a bright, sunny spot. Protect it from strong wind. Below -10°C it needs protection from frost. Watering: It needs plenty of water during active growth. The soil should never dry out completely, but it shouldn’t be constantly waterlogged either. Pay special attention in summer: watering even a few hours late can kill the tree. Fertilizer: Once every 2 weeks throughout the growing season. Pruning: Sweetgum branches are not cut during dormancy. This can cause the whole cut branch to die back. Prune after the growing season has begun. Maintenance pruning is also done during active growth. Pay particular attention to cutting off the terminal buds; otherwise the lower part of the branch develops poorly and may not produce new shoots. On sweetgum, cuts heal quite slowly.

Repotting: Once every 2 years, in spring, when the buds start to grow. It tolerates root pruning well, but be sure to keep a balance between the roots and the size of the canopy. Wiring: Only the fine branches of sweetgum can be wired, and they are damaged quite easily. Styling is done mainly by trimming and by alternatives to wiring. Note: Sweetgum has broad leaves and fairly long internodes, so great care is needed when styling it. It is better to make a large bonsai from this species, because it will be easier to work on and you will find it simpler to achieve a well-proportioned, beautiful bonsai.