Japanese maple trees (Acer palmutum) are grown primarily for their foliage, which turns crimson to golden yellow in the fall. Some weeping varieties provide winter landscape interest with arching silhouettes. Others exhibit glossy or textured bark. The tree's heights and growth rates vary by climate, species and cultivar, but it is considered a slow-growing tree.
Mature Japanese maple trees grow at a rate of 10 to 15 feet every 15 years. Their slow growth makes them suitable for container and specimen plantings. Dwarf varieties, such as Fjellheim and Kamagata, reach their full 8-foot height more rapidly than larger Japanese maples. The tallest Japanese maples reach maximum heights of 25 to 30 feet. Japanese maples grow fastest when young. They grow faster when supplied with optimum growing conditions.
The Japanese maples grow within U.S. Department of Agriculture Plant Hardiness Zones 6 through 9. They cannot tolerate heat or extreme cold. Japanese maples do best in moist, well-draining, loam soil. Avoid heavy soil and saturated sites, as Japanese maples develop root rot and are susceptible to fungal diseases. Their leaves are susceptible to sunburn, so site your plants in partial shade. Given temperate weather and a sheltered, well-draining site, Japanese maple should grow at a rate of 6 inches to 1 foot per year.
Although Japanese maple grows from seed, most cultivars grow from grafted stock, ensuring uniformity. You will most likely plant a young Japanese maple already established in a nursery. The tree's root system needs space to grow. Impaired root systems contribute to lacklustre growth and potential plant death. Plant your tree in a hole 50 per cent wider than the root ball. Remove any twine or ties from the root ball. Leave the burlap, if any, on the root ball to prevent root damage. Backfill the hole with subsoil, and then water the tree with approximately 1 gallon of water. Allow the water to seep into air pockets. Backfill with the remaining topsoil and tamp it lightly into place. Do not pack the dirt. This allows your root system and the rest of your tree to grow at a healthy rate.
(See reference 4 - PLANTING)
Containerised maple trees do best when planted in containers twice as wide as they are tall. Maple trees have shallow roots and need to spread out. Choose soils that are loamy and acidic with high amounts of organic matter. Organic matter helps aerate soil and retain moisture necessary for container plants, as containers dry out faster than traditional in-ground plantings. Maintain even moisture, and the Japanese maple grows at normal rates.