How to Create a Gorgeous Japanese Maple Bonsai Tree: A DIY Step-by-Step Guide

Love Japanese maples but aren’t sure you have room for them in your garden? Grow them as bonsai instead. Bonsai is an ancient art that involves pruning and training a tree so that it looks like a miniature version of the full-size object. Japanese maples seem to be perfect candidates for this growing technique. Start with this simple guide that includes expert tips for success.

Growing Japanese Maple Bonsai Trees

“Japanese maples are really great for bonsai because they’re a low-maintenance tree to begin with,” says Steve Pettis, a commercial and consumer horticultural agent for the North Carolina Cooperative Extension and a bonsai enthusiast for more than two decades. “If you’re using a white oak, which has the potential to grow to a hundred feet tall, it’s a lot more work than a bonsai tree, which in its natural state is only 20 feet tall or even 10 feet tall. A dwarf tree will be much easier to handle in a bonsai pot.”

Other qualities in favor of Japanese maples: They are more forgiving when it comes to pruning. The flexible branches are easily trained; and there are many interesting cultivars. Weeping cultivars like the burgundy 'Crimson Queen' or the green-leaved 'Waterfall' are ideal because the branches naturally curve downward like an umbrella. The 'Shigashira' has a very sculptural, dwarf form and small leaves, making it a favorite for bonsai.

Any species of Japanese maple can be used in bonsai, but Battis notes that varieties with palmate leaves (called palmettes) work better than those with cut leaves (called lacyleaf, cattail, or disctum). Cut-leaf Japanese maples are said to be more sensitive to watering, and are prone to wilting and browning of their leaves late in the season. He recommends the more vigorous Japanese maples for bonsai beginners.

Buy one or start one?

“If you’re a gardener, I recommend doing it yourself. Starting from scratch is much more beneficial,” says Pettis. “And it doesn’t hurt to have more than one. I have a couple. That way, if you don’t have one, you always have a replacement. But that’s how hobbies start. You get one, then you think you need two, and before you know it, you have 10.”

Those with less patience can order a pre-made bonsai online. “If you’re not the type who likes that process, you might want to buy one and treat it like a houseplant. But at some point, you’re going to have to deal with it by trimming the roots and the vegetation,” he says.

Choosing a container

“Bonsai literally means plant in a tray,” says Pettis. “So you’re planting a plant in a shallow tray to try to replicate the growing conditions on a mountaintop, where a small tree has grown in a shallow amount of soil and the tree naturally dwarfs.”

Containers range from shallow trays 2 inches high to large pots 8 inches deep or more, but all should have drainage holes. Although the size of the container depends on the eventual size of the bonsai you hope to grow, the style should complement the specimen plant itself. For an artistic effect, many Japanese maple bonsai trees have an informal, upright shape with a broken, multi-stemmed, or slanted trunk.

Planting

Carefully remove the soil from around the tree’s roots with chopsticks, then gently cut the roots to a one-to-one ratio with the branches. Cover the drainage holes with mesh, then secure it in place with glue or wire. Thread a U-shaped wire, facing up, through the mesh and the two drainage holes, then add a half-inch of gravel and equal amounts of soil. Spread the tree’s roots over the soil and secure the tree with the U-shaped wire.

“Most people will use a flexible copper or aluminum wire to connect the roots to the pot, because it’s easy to pull them out of the pot if you don’t,” says Pettis. Fill the rest of the container with potting soil and press it down firmly with your fingers, making sure not to cover the expanded root collar at the base of the tree.

“You can use any good quality potting soil—that’s what I use—but they sell special bonsai soil at bonsai shops or online,” says Pettis.

Pruning

Perform light pruning and pinching during the growing season. Save heavy pruning for your Japanese maple bonsai tree for late fall or winter. “You can probably do it a few times a year, maybe early in the season, or late in the season,” says Pettis.

It’s best to prune the roots in the spring before the tree’s leaves emerge. Work in the shade and dip the roots frequently in a bucket of water to keep them from drying out. “They’re usually taken out of the pot and root pruned once a season and then put back in the same pot,” explains Pettis. “Don’t bump into the pots, they stay in the same pot forever,” he adds.

Training

To change your bonsai tree’s habit, wrap copper or aluminum wire around the branches after the tree has regrown in the spring. Bend the branches to the desired shape, then remove the wire after 6 months. To make the branches curve downward like a waterfall, weigh the branches down with paper clips or wooden clothespins.

Care

Shallow pots dry out quickly, so your Japanese maple bonsai tree may need to be watered daily. The more sunlight they get, the more water they need.

Plants will also need fertilizing. Some growers use slow-release organic granular fertilizers, which are released gradually throughout the season. Bates uses a water-soluble fertilizer every three weeks, starting after the last spring frost and ending in early August. “Again, it’s a matter of feeling. If your plant starts growing like crazy and overgrowing, you don’t need fertilizer,” he says. “Planting—a lot of it is based on intuition.”

Placement

Japanese maple bonsai trees love morning sun and afternoon shade, so they grow best on the east side of a house. “You want them to get sun, but not during the heat of the day, but real intense sun,” Bates says. “That will help you with your irrigation regimen, because otherwise, if the plants are in full sun, you’re going to have to water them twice a day.” The indirect sunlight will help the plants avoid leaf damage when temperatures are above 85 degrees Fahrenheit.

Pests and Diseases

Japanese maples are sometimes attacked by sap-sucking aphids, which can be treated with an insecticide spray. Veracillium wilt is a fungal disease that is easily spread by pruning. If you notice black spots on freshly cut wounds, disinfect your pruning tools with a 10 percent bleach solution between cuts to prevent the spread of the disease.

Winter Safety

It’s best to keep your Japanese maple bonsai outdoors year-round, as they need cool weather to encourage dormancy. Protect the plant from wind and enclose the containers with bubble wrap or place them in a cold frame if temperatures drop below 15 degrees Fahrenheit.

“If temperatures are going to drop below freezing, you might consider bringing them inside, but otherwise what most people do is tie the plants together and put something like straw bales around them and then let the snow fall on them and insulate them,” says Pettis. Wrapping with wood chips or leaves, which can cause root rot in wet winter weather, is not recommended.

Mistakes to Avoid

When properly cared for, a Japanese maple bonsai tree will grow and flourish for years to come. However, there are some common mistakes to avoid.

“The biggest mistake I see is people loving their plants too much—over-pruning, over-fertilizing, over-watering, that kind of thing,” says Pettis. “You kind of neglect them, let them grow, water them as needed, let them dry out to a certain extent between waterings. But don’t overdo it. It’s a passive type of management where you let them do their thing. Then you occasionally tweak them until they take shape and do what you want them to do.”