Maples in containers need well-drained potting mix, frequent watering, and regular repotting. Roots in pots are vulnerable to cold, so even in temperate climates, it's wise to insulate the pot before planting and wrap it well every winter or move it into a cool, sheltered place such as an unheated garage or crawl space. The different cultivars of Japanese maple don't keep their distinctive characteristics through seed propagation, so they are grown from sections of stem grafted onto a rootstock, usually of seed-grown A. palmatum.
One of Japanese maples' chief attractions is their vivid fall color, but many kinds have colorful leaves throughout the season, and sometimes leaves that change, chameleon-like, from spring through autumn. Another useful attribute is that, though full sun is best, most Japanese maples can tolerate some shade—not deep shade, but the kind of dappled sunlight that finds its way between buildings and trees into city gardens.
Some cultivars are as tall as the forest species. Others are tidy little mounded shrubs. They may be upright and vase-shaped or have horizontal or cascading branches. Some have a deep red tint to their leaves; others have foliage that is bright green, creamy white, yellow, pink, or orange. Nearly all are spectacular in fall.
Every Japanese maple has leaves with five to seven pointed lobes. In some varieties, however, the lobes are much more slender, often edged with teeth, giving the foliage an overall lacy effect—leading them to be called laceleaf maples or, with finer leaves, threadleaf maples. Usually, those plants have a mounded or cascading form.
In Zone 5, late frosts may frazzle the tips of early leaves. Verticillium wilt, a fungal disease spread through the soil or grafts, is sometimes a problem, especially if the tree is stressed by underwatering, overwatering, or too much sun or fertilizer. Failing branches should be pruned out immediately and the tree given the conditions it needs to stay healthy. If a tree is severely afflicted, it's time to give up on it. But the biggest vulnerabilities of Japanese maples, especially to the laceleaf and threadleaf types, are sun scald or drying out in hot winds. So whether in containers or in the ground, shelter these maples from the prevailing wind.
Because of their distinctive beauty, Japanese maples are usually planted as attention-grabbing specimens. In the traditional design of the Anderson Japanese Gardens in Rockford, Illinois, the summer garden is blanketed in green and relies on punctuation by maples with colorful foliage such as Acer palmatum 'Crimson Queen,' 'Garnet', and 'Bloodgood' in key focal points, notes curator Tim Gruner.
Japanese maples lend themselves to subtler effects, as well: Cascading types are a favorite of Andrew Bunting, curator of the Scott Arboretum at Swarthmore College in Swarthmore, Pennsylvania, who likes to see them draped gracefully over the top of a wall.
Dallas landscape architect David Rolston uses Japanese maples in his designs for texture and contrast. "Any time you can use something soft in a hot climate, it is welcome," he says. Texas is outside the maples' comfort zone, so it is crucial to provide afternoon shade and regular water.
A Japanese maple may be the high point of a garden's design, but be sure to choose and site the plant with an eye to its needs. Don't plant the maple too close to a house or walk, where it will require major pruning or where people may trample on its root zone. It is better to buy a cultivar that won't outgrow its space than fight to keep a too-large plant in bounds. Fortunately, the wide range of Japanese maples means that there is the right plant for any spot.
Jon Carlson of J. Carlson Growers in Rockford, Illinois, which specializes in Japanese maples, questions customers closely about their growing conditions and is careful about recommending finicky cultivars. "We don't sell them to anybody that wants to buy them," he says. "It's like helping a puppy find a good home."
Japanese maples can often be found at home centers for $50 or $75 in spring, but it is key to investigate the cultivar's needs and ultimate size before buying. A too-big or too-delicate tree is no bargain.
In the leafy suburbs of Chicago, many front yards feature Japanese maples whose purple leaves shine like rubies when they catch the sun in spring. But even in deep shade, green-leafed types manage to make a statement. Between tall shade trees, upright maples grow 15 or 20 feet high and glow like torches in fall. They are as attractive in a grand, sweeping garden as they are behind a city town house. Removed from the forests of Asia, Japanese maples look at home in almost any yard.
Learn how to prune a Japanese maple.