Japanese maples should generally be kept outside, including the bonsai variety. They like sunlight but should be moved to the shade in the heat of midday. It can even stay outside to fall into dormancy in the winter, as it is a hardy plant, but should be protected from temperatures below 14° Fahrenheit.
Japanese maples need to be watered daily while they’re growing, and sometimes more than once a day, depending on the drainage of the soil, according to Bonsai Empire. A general rule of thumb is to water once the soil is slightly dry. The soil should never be allowed to dry out completely, and when watering, be sure to soak it thoroughly so as to wet the whole root system. This means watering until it seeps out of the drainage holes. Rainwater is best, as it is slightly alkaline, in which these trees thrive, but if you only have tap water, it won’t hurt the tree.
Provide your Japanese maple with high nitrogen fertilizer in the early spring every two weeks, says Bonsai Outlet, as newly unfurling leaves need the nourishment. Later, fertilize with a much more diluted solution every other week in summer, but taking care to not feed with the regular strength and frequency at summer’s hottest. In the late summer to early fall, use a nitrogen-free fertilizer and taper off before winter hits. Be careful not to fertilize too little or too much to ensure a well-proportioned tree.
To keep your bonsai tree under control and in the shape you wish it to be, you must prune it. Bonsai Experiencementions pruning unsightly growth and protrusions and pruning the tips of the branches to keep them from growing. You may even snip away individual leaves or groups of leaves. While the top of the tree grows more rapidly than the lower branches, it’s important to observe the entire tree for growth regularly, as it can quickly get out of hand if pruning is neglected.
Another technique for shaping your bonsai is wiring the branches. This involves wrapping wire around flexible branches and positioning them in the way you wish for them to grow. For Japanese maples, the perfect time for wiring would be in the winter, when the cold has already stripped away the tree’s leaves, making the branches significantly easier to wrap. Branch growth during the spring and summer can also cause the wire to bite into the branch, causing scars. Use anodized aluminum wire, and, according to Bonsai Empire, starting out with 1mm, 1.5mm, 2.5mm, and 4mm thick wire should be enough to start with. It’s also best to purchase some raffia and soak it before applying it to larger branches to prevent the wire from damaging them. Once your tree is all dressed up in raffia, you can take two branches of similar size and wire them together in several places on the tree while wiring all other branches singly. Start by wrapping the wire around the trunk, and then wrapping the wire around the branch or branches you desire from base to tip. Once wired, you can bend them into the preferred shape, making sure the wire will hold it. Once a few months have passed and the branches are set in their shape, and before the growing season, unwire them and remove the raffia.
Repotting requires having the right soil and pruning the roots. Bonsai Outlet says to repot every one to two years for trees less than ten years old and every two to three years for older trees in early spring—before the buds open. Be sure to prune the roots so it fits in its container, but cut away no more than half of the root mass of young trees, and cut away even less for older trees. Most sources recommend using a soil mixture of akadama, pumice, and lava rock, but as long as the soil drains well, it should be fine. Also, refrain from fertilizing directly after repotting, waiting for about two weeks.
The simplest way of propagating is growing the maples from seeds, but you can also take a cutting from a living maple in the summer. If you are propagating this way, all you need to do is cut a new branch from the parent tree, removing the lower leaves. Then place the cutting into a pot of soil, burying at least one leaf node, Agverra instructs. They also suggest putting the pot in an open plastic bag to keep moisture in, ensuring it remains wet at all times. Put the pot in a warm spot, but not in direct sunlight. When it begins growing new leaves, this is a sign that it has rooted.
Obtaining a Japanese Maple Tree
As mentioned above, you could propagate a new tree by asking around to see if anyone is willing to give you a few cuttings. However, local DIY stores, such as Lowe’s or Home Depot may already have a few for sale, or perhaps a local nursery. If all else fails, a simple Google search will produce many results, from seeds to seedlings, to even already trained bonsai’s.
Diseases and Pests
Japanese maples are pretty hardy, but there are still a few things that you should watch out for. Japanese beetles, for instance, will destroy all leaf growth if allowed. Other pests include scale bugs, mites, and mealybugs, according to Gardening Know How. The damage will manifest as small bumps or “cottony spots” on leaves and twigs. Wilting, yellowing, or puckering leaves can indicate aphids, and borers will show themselves as clumps of sawdust. Taking care of pests is as easy as treating your plant regularly with pesticide. As far as diseases go, canker can attack the tree, presenting itself as sap oozing from the bark. Yellowing, prematurely falling leaves is a sign of Verticillium wilt, and leaves rotting and falling are symptoms of Anthracnose. Pruning appropriately and clearing fallen debris from the base of your tree should prevent these diseases. Keep a close eye on young trees, however, as they have a higher chance of succumbing to diseases and the attacks of insects than that or older trees.