Maples as Bonsai Part 1

By Marius Greeff

The Maple is one of the most popular trees in Japan, not only as ornamental shrubs in the garden, but also for bonsai enthusiasts. The horticultural history of Japan would certainly be unimaginable and incomplete without the Maple tree being mentioned as part of it. For hundreds of years this tree has found its way into the hearts and gardens of the Japanese. As far back as the seventh century its beauty was praised in a book of romantic poems, Man-Yoshu, published in 614 A.D.

During the peaceful Edo-era (1603 - 1867) when horticulture flourished in Japan, the zeal and enthusiasm for cultivating Maples reached a peak. People went out into nature not only to enjoy themselves, but they held Maple-viewing parties and also brought the trees back to their homes as precious garden plants or as potential bonsai. New varieties and new forms were constantly being sought. Records from those years show that as many as 200 named cultivars existed; many of these were lost during the last war.

As in those far off days, Maples are still cherished today because of their brilliant Spring growth, bright green leaves in Summer, red or gold foliage in Autumn and the shapely appearance of branches in Winter.

The Maple has a strong genetic tendency to proliferate into many variations and mutations. In the very early days of horticulture the Japanese collected mainly the outstanding and beautiful forms of Acer palmatums which they saw on trips into the wild. These consisted of seedling variants. In addition, as new bud mutations were discovered, the trees were also propagated vegetatively. As the number and variety of these plants increased, they were planted in close proximity, resulting in cross-pollination. The parents of unusual form thus gave rise to additional hybrid variants and this process continued to expand over the years. The genetic potential for new and interesting seedlings increased still further and as might be expected during a period of 300 years, the process has yielded an enormous number of selections and cultivars.

For the Maple the war years meant a sad time. Indeed, for many varieties, it was the end. The poor economic conditions of the last World War caused many cultivars to be destroyed and lost forever to cultivation. Areas previously devoted to ornamental horticulture were now used for food production and old Maples were cut down to alleviate shortages of wood for fuel. One nurseryman tells how his ancestors put together a very large collection of cultivars during several generations, only to have many of the trees burned as firewood.


These trees are remarkably adaptable to differing soil and climatic conditions, as one can gather from the fact that they are found throughout the world. In Japan itself one finds them growing in a wide range of soil conditions, on most of the islands and in varying degrees of climatic exposure, from 100 to 1300 meters above sea level.

Although the green varieties can take full sun very well, extremely hot conditions may cause leaf scorch. Afternoon shade will aid in preventing this. The same applies to the variegated leaf types. Red cultivars also appreciate some shade but will not develop their typical deep red colours without strong sunlight for at least part of the day.

The ideal soil for Maples is a sandy loam with a low-to-medium organic matter content. These trees do quite well in less-than-perfect soils of most types. In very tight or very sandy soils the growth rate will be reduced somewhat, so the soil mix should be adjusted accordingly and should have good water retention capabilities as well as good drainage. As the roots of maples are neither very deep nor of a penetrating nature, placing a straw mulch on the soil will help to retain moisture and will keep the roots cool in the heat of summer. Heavy moss over the surface would have the same effect.

According to Teiichi Katayama, the best soil mix for Maples is 7 to 8 parts loam to 2 to 3 parts river sand. John Naka suggests a mixture of one part soil, two parts mulch and two parts washed sharp river sand - the mulch for retaining moisture. Depending on the development wanted, vary the mix, using more sand for slower growth.

Maples do not grow well in very alkaline soils so that a too high pH level will need adjustment with acid fertilizers or neutralising soil additives like peat moss. In nature the acid soil in which azaleas do well, is well suited to Maples.


The age of your tree will determine the frequency of re-potting. Older trees usually grow at a slower rate, not requiring much nourishment, whilst the livelier, younger trees grow more rapidly filling the container with their roots and consuming all the nutrition in the soil within a comparatively short time.

Trees will show definite signs of when re-potting is overdue. Indications are: 1. the fading of the colour of the leaves; 2. withering of the lower leaves and even branches; 3. hardening and swelling-out of the surface because of overgrown roots. In the latter case, the soil has difficulty in absorbing sufficient water and the ventilation spaces in the soil become clogged with fine hairy roots which eventually choke up the natural supply of air and moisture to the tree. Adequate drainage is very important. The drainage holes should be checked for signs of root blocking.

When re-potting an ESTABLISHED Maple, one with a well developed system of fibrous roots, do not change the soil completely. Remove soil from the outer edge of the root-ball and replace this with fresh soil. This will allow for just enough new root development to keep the tree heal thy but will not give too much boost so that top shoots become too strong and new leaves too big. Re-potting Maples unnecessarily will cause the tree to become over vigorous, soon resulting in the loss of its bonsai shape.

When re-potting, take the opportunity to inspect the roots. Most of the roots should be evenly distributed throughout the entire area of the root ball, indicating a thorough watering. Heave roots in the upper section of the root ball are the result of poor watering, causing small secondary and heal thy roots to be located at the bottom of the pot.

The best time for re-potting is at the end of the dormant season, just prior to when the main growth starts to appear - eg. the new buds start to swell, but have not yet opened into new growth.

Repotting of Maples should be done once a year or at least every second year because of their tendency to grow a root mass in a very short time. With older trees, and trees still in a training pot, repotting is obviously not needed as often. Once repotting has been completed, secure the tree to the container and place the tree in a shady sheltered spot out of the wind, for at least two weeks.


Glazed containers of contrasting colours are used for deciduous trees although unglazed pots are acceptable. Select the colour according to the colour of the leaves (consult the Spectral Ring of Colour in J.Naka, Techniques II, p. 355). Maples known especially for their autumnal foliage display are usually complimented by willow - or pale green, off-white, grey, black, dark - and sky-blue, or even brown pots.

Oval and rectangular containers are used when the branch spread or the branches are to be emphasized. Square or round containers are used when trunk line movement is the major feature. Deep containers are always better for the Maple in areas where the summers tend to be very hot and the winter very cold.


Because Maples tend to develop lush foliage and have a very fibrous root system, these trees can take more water than any other bonsai. Whatever watering schedule you follow, remember that uniform supply is very important, especially as they come from a naturally humid environment. Avoid flooding trees with water at irregular intervals. Unless the trees are regularly watered, mid-summer leaf drop or leaf scorch might result.

Watering should be done two or three times a day, in the morning and early evening during summer, making sure that at least one watering includes the spraying of leaves; making sure also that the leaves are not in full sunshine when sprayed, as this could also result in leaf-scorch.

Determine the correct amount of water necessary for the soil mix used, your environment and the size of the container, and so avoid water logging. Over watering can be worse than under watering. It is no wonder the Japanese believe that proper watering takes three years to master. Good drainage, ventilation and light are all very important factors in ensuring a healthy tree. As maples are vigorous growers, be on the look-out for roots blocking the drainage holes.

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Random Bonsai Tip

Using deadwood can improve and enhance a number of problematic aspects in the design of a tree. If the tree doesn't have a satisfactory apex, create one with a jin. A shari can be used as a focal point or it can give movement to an uninteresting trunkline.