Growing Japanese Maple Trees

Don Faust
Adams County Master Gardener

(6/7) Sometimes, even after our best efforts, we end up planting the wrong tree. Last fall, in my search for the perfect Japanese Maple, I incorrectly planted a Chinese Maple instead. Being someone not easily deterred, I used my recent Master Gardener training to learn all that I could about Japanese Maples so I wouldnít make the same mistake twice. Here is what I have learned so far.

Japanese Maple trees are from the species Acer palmatum and are truly unique trees. There are over 1000 different cultivars. Some leaf out in brilliant reds in spring, change to green by summer, and finish the fall in yellows and oranges. Others start red and stay red till their leaves drop in autumn, revealing their sculptural forms. Leaves can be palm-shaped or lacy, almost feathery, and their available color palette includes red, green, orange, purple, white, and pink. They can grow as tall as 50 feet or be as short as 3 feet. Cultivars come in a variety of forms including upright, broom, weeping, cascading, dwarf, and shrub. Some like full sun, some like full shade, and others like conditions in-between. Some tolerate poor soil, some demand a rich and fertile footing. Some are very water hungry, while others tolerate drought well. You get the picture? Japanese Maples are like children.: They might have the same parents, but they can be very different.

There are several steps to ensure you and your Japanese Maple have a happy partnership. First, make sure you have a soil test and know the pH of your soil. Japanese Maples like slightly acidic soil and do not tolerate heavy alkaline soil. Also, they typically donít do well with clay, heavy or poorly drained soil as it holds the water and gives the tree "wet feet." Second, know where you want to plant it and how much sun it will receive each day. Some cultivars love full sun, while others will not tolerate it. Morning sun and afternoon shade will suit most maples best. Some cultivars are okay being exposed to higher winds, while others are more delicate. Third, know the size limitations for your tree. Some trees grow very tall and others very wide. While Japanese Maples typically donít have aggressive root systems, it is generally not a good idea planting a large tree close to your house as roots can potentially damage your foundation and branches can damage your roof. Fourth, know the look you want for your yard. Japanese Maples are very ornamental and come in many shapes, sizes and colors.

A good resource to learn about Japanese Maples is the book Japanese Maples: The Complete Guide to Selection and Cultivation, Fourth Edition by Gregory and Vertrees. In addition, there are numerous websites dedicated to the selection and care of Japanese Maples. It truly is a marriage of all the factors discussed above to determine the proper match for your yard.

Once you have chosen the right tree at your nursery, here are some helpful hints:

  • Keep plants moist and in the shade until planting. When planting, it is preferable to find a location providing morning sun and afternoon shade.
  • Soil preparation with organic matter is important, especially if the soil is clay. Incorporate about 10-20 percent organic matter into the soil to help with drainage and aeration.
  • Dig the hole 2 to 5 times the size of the root ball but donít go any deeper. In poorly drained or heavy clay soil, the plant is best placed higher than its original planting depth at about 4 to 6 inches higher than the surrounding area.
  • Mulch after planting to reduce the need for frequent watering and for protection of the treeís shallow roots. Apply a loose mulch, such as wood chips or pine needles, over the planted area to a depth of 4 to 6 inches. Be sure to keep mulch several inches away from the trunk of the tree.
  • Keep pruning of newly planted trees to a minimum. After maples are established, the preferred time to prune them is between mid-July and August, a period when sap won't run from cuts. The trees should not be pruned in early spring when buds are breaking during leaf expansion or in late autumn because the wounds wonít have enough time to heal before winter conditions of freezing or dampness. Maples should be given a thorough pruning every three years and minor "touch up" pruning annually. A thorough pruning involves removing dead limbs and crossing branches (or branches that will cross in the future). A certain number of branch tips will have died back, and these tips can be snapped off with your fingers or larger branches cut with a pruning tool.
  • Do not fertilize newly planted trees until the second growing season. Begin in the spring with fertilizer containing something organic like fish emulsion fertilizer, Millorganite, or another organic fertilizer. Donít apply the typical vegetable garden fertilizer because it usually contains too much nitrogen. Most ornamental plants physically cannot grow fast enough to use that much nitrogen and the overload of nitrogen will kill them almost immediately.
  • Water regularly until plants are established. In a hot, dry summer, it is always best to give your tree a deep watering once a week to ensure there are no drought issues.

Enjoy your Japanese Maple. With a little investment in time and some TLC, you will have a beautiful tree to admire for years to come.

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