Good drainage is probably the most critical factor when planting a Japanese maple. Like many other shrubs and small trees, Japanese maples prefer well draining, slightly acidic, and slightly organic soils. This is primarily important when getting the tree established to avoid drowning the root system or inviting soil born fungi or mold into the root system. Heavy clay soils should be amended with soil conditioner or compost (even when on a slope), and the maple should be planted on a slight mound. Mulching can help hold in moisture near the surface, but it should never be piled on the trunk.
Japanese maples do not have unusually high moisture requirements once established. When planting in the late fall or winter, weekly watering (including rain) is more than sufficient. When planting in spring or early summer, newly planted maples should be watered at least 2 to 4 times per week depending on heat, wind, and the size of the root ball compared to the size of the upper portion of the plant. Late summer plantings may require daily watering for the first few weeks, followed by moderate watering until leaf drop. After one or two years, most trees should be partially established and may only need watering during the dry periods of the summer. Note that unusually sandy or dry areas may need additional water even after establishment.
Late Frost Protection
Japanese maples often leaf out a bit early and can get damaged from late spring frosts in certain areas. Fine hairs on the young leaves and stems add some protection from light frosts. However, late freezes after leaf out can be dangerous. It is recommended to cover Japanese maples with some type of cloth material if you suspect a late frost (primarily when young or if severe freezes occur). Plastic covers are not recommended. Of course, if the tree is still containerized you can move them to more sheltered location if needed.
Japanese maples require little pruning. However, careful pruning can add to the character and beauty of the structure of the tree. Dead branches in the interior can be removed any time, but other major pruning should be done in late fall to early winter (not late winter or early spring because of bleeding). Summer pruning from late May to July is also acceptable. Crossing or rubbing branches should be removed early to improve structure. Most other pruning is primarily aesthetic.
Japanese maples do not need a great deal of fertilizer. A light application in spring is preferable. We recommend a good slow release or natural fertilizer to reduce salt build up which can cause leaf scorch and twig dieback.
Container growing can be a bit more difficult, but most Japanese maples are well adapted to being grown in pots or planters. Some gardeners actually have more success with container growing when soil conditions are poor, especially with small maples. Excellent drainage is the most critical aspect. A good potting mix is critical. Watering needs are much higher for containerized plants. Maples may need thorough daily watering during the summer in sunny conditions. Shady areas may only require watering two or three times a week during the summer. Some watering during the winter is recommended if conditions become dry, but rain or melting snow is usually sufficient in most areas for Japanese maples. Only the best slow release or natural fertilizers should be used in containers. Some additional winter protection may be needed for container grown maples since the root systems are not insulated as well as in the ground. This is especially true when dealing with smaller maples.
Most Japanese maples are easily cared for and are adaptable to many growing conditions.
Most Japanese maples prefer morning or partial sunlight. Most varieties can adapt to full sun conditions, but we recommend more protected locations for several reasons. Most “red” varieties need some direct sunlight to develop the best color, but they appreciate afternoon shade to reduce leaf scorch and color bronzing.