Japanese maple trees (Acer palmatum) are a diverse group of shrubs and small trees. Usually grown as ornamentals in the home landscape, they are also popular bonsai plants and grow well in containers. They are winter-hardy to USDA zone 5, and can be given winter protection in even colder areas if grown in pots. They will thrive in full sun in cooler regions or dappled shade where it is hot. Older Japanese maple trees are somewhat drought-tolerant. For all of their beauty and value, the Japanese maple is an easy plant to grow and to care for.
Remove all turf and weeds within a 2-foot diameter of the Japanese maple. The young roots will not thrive if they are forced to compete for water and nutrients. Keep the area weed-free for the first three years that the tree is in the ground.
Water the young Japanese maple deeply and consistently, maintaining moist but not soggy soil, until it reaches 3 years of age. After that, the tree will require less water and, in fact, is drought-tolerant. Use a soaker hose to deliver water slowly to the tree's root zone. According to experts at the University of California (Tex A&M) the single thing that the gardener can do to assure that the one-year-old Japanese maple succeeds is to water frequently.
Mound up soil to a height of 5 inches and 8 inches in thickness. Form this soil into a ring around the Japanese maple tree, at a distance of 2 feet. This ring is known as a watering well and helps to concentrate the water to the young tree's roots.
Add a 3-inch layer of mulch inside the water well, 2 inches away from the trunk. Mulch helps keep the soil moist and cool and discourages weeds.
Exercise caution when choosing fertilizer for the tree. Do not use slow-release fertilizers on the Japanese maple. According to Carolee James, Master Gardener with the University of California Cooperative Extension, this type of fertilizer will burn the young tree's leaves. They suggest using an all-purpose water-soluble fertilizer, diluted to half the strength recommended on the package, in the spring and summer.