Turning a Japanese maple (Acer palmatum) into a bonsai tree is an interesting project. There are certain trees that will grow very beautiful when made bonsai. The tiny maple tree will grow just like its normal, large version, and the leaves will also change color as fall arrives. You only need a few things to make this project as well as a great interest in making bonsai plants.
Method 1 of 4: Selecting Maple Stems for Grafting
Step 1. Graft the soft woody stems of the maple cultivar of your choice, in early summer
Maple trees will grow easily from grafts. Choose an attractive maple tree branch. The size of the branch should be about the diameter of your little finger.
- There are many cultivars of Japanese maples that can be bonsai. Choose as you wish. Some cultivars grow larger than others, some have hard bark, and some require grafting.
- Make several grafts so you have a spare and make sure one of them grows well (sometimes the tree roots are weak, rotting, or not growing at all).
- You need to know, red-leaved Japanese maple cultivars tend to have weak root tissue and usually have to be grafted onto the rootstock of another tree. If you don't know how to graft or don't have acquaintances who can help, it's best to avoid bonsai red-leaf cultivars until you have more experience with them.
Method 2 of 4: Preparing for the Graft
Step 1. Make a wedge around the base of the stem, where the roots will grow later
Slice around the bark until it reaches the hardwood inside.
Step 2. Make a line of slices under the first slice, 2x the size of the stem
Step 3. Slice a straight line to connect the first and second slices
Step 4. Peel the bark that is between the two slices
You can peel the bark off easily. Do not leave a layer of cambium (green layer under the bark) at all.
Method 3 of 4: Waiting for Roots to Grow on Maple Grafts
Step 1. Sprinkle root hormone powder or apply root hormone gel on the top of the sliced stem
Wrap the section in wet sphagnum moss (or you can use coconut husk), then cover it with plastic and tie it tightly.
- Keep the sphagnum moss wet. After a few weeks, you should see roots growing through the plastic.
- As an alternative to sphagnum moss, use a good quality sandy compost. Keep this compost medium moist.
- Roots will grow in about 2-3 weeks if the grafted stem is healthy and the conditions are warm and moist.
Method 4 of 4: Growing Maple Tree Bonsai
Step 1. Cut the grafted trunk from the main tree
As the roots grow more and more and turn brown, cut the graft by cutting it just below the new root.
Step 2. Place small pebbles at the bottom of the pot for drainage
Partially fill the container with good quality humus (a good mix consists of 80% bark and 20% peat, as both tend to stimulate fine fibrous root growth and provide good drainage). Open the plastic wrap and do not disturb the roots. Plant this new tree and add soil as needed to strengthen the tree in the pot.
The addition of sphagnum moss will be very useful especially in hard water areas (water that has high mineral content)
Step 3. Plug in a small rod
Turus will help keep the tree in place as it grows. Any movement can damage the tree's fragile roots.
Step 4. Enjoy the new tree
Find an outdoor area suitable for storing bonsai, such as a veranda, garden bed, or patio. Bonsai is not a plant that is suitable to be placed indoors. If you bring it indoors, keep it for only 1 or 2 days, then return it outside. Bring in bonsai for only one hour each day in winter.
- Shade the maple tree bonsai for the first few years. Don't leave the bonsai outdoors where it's reached by frost for the first 2 to 3 years because the tree may die. Do not place the plant in a windy place, and do not place the bonsai in a place that is exposed to direct sunlight all day.
- Fertilize the bonsai with a balanced fertilizer after shoots appear until late summer. During winter, fertilize with a low nitrogen or no nitrogen fertilizer.
- Don't let the maple bonsai dry out. The maple bonsai should be in slightly damp conditions at all times. If possible, use rainwater for watering instead of tap water, as rainwater is much healthier for trees. Water the bonsai regularly so that the plant grows healthy.
- Learn to style your bonsai once the tree has grown strong. This is the time for you to do what nature usually does, and set the tree to look like a bonsai. Bonsai should be carefully trimmed and tied with wire. It takes a lot of practice to get it right, but this is part of the fun of growing your own bonsai.
- For a description of the various cultivars of Japanese maple, see Japanese Maples: The Complete Guide to Selection and Cultivation, Fourth Edition, by Peter Gregory and J. D. Vertrees (ISBN 978-0881929324). This book will help you understand the behavior of tree growth, because in general a bonsai grows more or less like a large tree planted in the ground.
- You can grow Japanese maple bonsai from seed if you wish. This method will take a lot longer, of course, but may be ideal if you don't want to grow a bonsai from a tree graft. Types of Acer palmatum can be grown easily from seeds. When grown from seed, the appearance of a maple tree can vary greatly, and this can be one of its main attractions.
- Transplanting Japanese maples is best done in mid to late spring, after the foliage has grown back.
- Soft aluminum wire or copper gauze can be used to shape the tree in any direction you want. Wrap the wire starting at the thickest and strongest part of the trunk, then wrap it around the trunk loosely. Do not wrap the wire too tightly as the tree can be damaged and will leave a scar. Just wrap it around the stem, don't suffocate it.
- Move the bonsai tree into a new pot in the spring every 2 or 3 years, for optimal growth. Cut about 20% of the tree roots on each side and base. Water the bonsai in the new pot thoroughly.
- Cut off the new shoots after 2 to 4 mature leaves have grown. Do this step throughout the year.
- In areas with hard water, add an acidifier (organic acid) to the soil in the pot, twice a year.
- Aphids really like the buds of the newly grown Japanese maple. Exterminate as soon as possible, otherwise these pests can make the shape of the leaves become deformed.
- If the leaves remain green and do not change color in autumn, it means that the bonsai is receiving too little light and should be propagated.
- Do not move or disturb the sphagnum moss during this process.
- New roots are very fragile and easily damaged. Be careful when opening the plastic and planting the bonsai in a pot.
- Do not wrap the wire too tightly when forming the tree. Wires that are too tight can damage the tree and leave scars that will take years to heal. Tight ties can also change the shape of the tree as it grows.
- Root rot caused by too much watering or compressed water in the soil is the main enemy of bonsai plants. Make sure the soil has good drainage and don't over-water. If water is seen standing on the surface, it means that the quality of soil drainage is poor and the planting medium must be replaced.