Japanese maple is a slow growing deciduous tree that is cold hardy in USDA planting zones 5 through 8. The easiest way to propagate Japanese maple is to look for “volunteers” on the ground beneath the tree. In the plant world, volunteers, which are also called seedlings, are plants growing naturally from fallen seeds. When it comes to the Japanese maple tree, the wings of the seeds can carry the seeds away from the tree. It can take up to two years for the seeds to germinate. Shown above are the red-winged seeds of Japanese maple in late spring.
Locate volunteer seedlings
Look beneath the Japanese maple in the spring for the seedlings. In the image above, about six tree seedlings appear in less than a two square foot area. I counted more than 100 seedlings in the surrounding area. Choose seedling that are at least 2 inches tall, though taller is better. Water the seedlings the day before you harvest them.
Push away mulch to expose the soil around the seedling. Use a hand trowel to remove the seedling. Push the hand trowel into the soil about 2 inches from seedling. Dig around the seedling in a circle. Gently lift the seedling and immediately plant. Below is a full-grown Japanese maple tree.
Plant Japanese maple seedlings in an area large enough to accommodate the tree’s growth potential, which is up to 25 feet tall and wide.
Plant in the ground or in a flower pot that is at least 6 inches in diameter. Potted trees will need an increasingly large size pot as the tree grows but a seedling 2 to 3 inches tall can remain in a 6-inch pot for several years. The seedling can be planted any time of the year when the ground is not frozen. If planting in the summer, an overcast day is preferred.
Dig the hole for the seedling three times as wide as the hole dug to harvest the seedling. Dig the hole to the same depth as the harvested seedling. The objective is to loosen soil to encourage easy root growth horizontal.
Place the seedling in the center of the hole. The seedling should be at the same level in the new hole as it was previously in the ground. Back fill the hole with soil removed from the hole. The potted Japanese maple tree shown below was once a seedling about 3 inches tall that I transplanted to a small flower pot. It took about 10 years to reach the height it is now.
Water around the root ball to saturate the soil. Spread 2 to 3 inches of mulch such as pine chips or leaf mold around the seedling. Water every seven to 10 days the first two years, spring to fall. After that, rainfall alone should provide sufficient water.
If planting in a pot, water at least weekly during the heat of summer. Water about twice a month through the winter if there is no snowfall to provide moisture.