The Japanese red maple (Acer palmatum atropurpureum) is a small, popular ornamental tree. This slow-growing tree can reach heights of 30 feet and has distinctive, twisting branches. Known for its striking and graceful canopy, deep purplish-green summer leaves and brightly colored fall foliage, the Japanese red maple is one of the hardier of the small ornamental trees, although it can suffer from a few problems.
The Japanese red maple tree is more susceptible to leaf scorch than other small trees, according to Christopher Starbuck of the University of Missouri. While leaf scorch is sometimes thought to be a disease by home gardeners, it is really caused by poor conditions in the climate. Most often, leaf scorch happens when there is an extended period of hot, dry weather followed by hot winds, or when bright sunlight hits the tree after a long period of gray weather. This causes the leaves to lose water faster than it can be replaced.
The primary symptom of leaf scorch is the appearance of yellow spots or streaks on the leaves of the tree. Watering the tree well, protecting it from hot, drying winds, adding mulch around the tree and giving the Japanese red maple a generous feeding of potash fertilizer in the spring can help prevent leaf scorch.
The bark of a Japanese maple is thinner than that of most other maples. This can cause the tree to be easily damaged by garden equipment. These open wounds are an access point for fungi or even a deadly disease such as verticillium wilt, which will cause the tree to die suddenly.
The Japanese red maple tree can also suffer from embedded bark. Also called included bark, this happens when bark becomes trapped between a branch and the trunk of the tree. This weakens the attachment of the branch and often causes it to fall off later. Prune the tree so that there are no cases of embedded bark and so that no two large branches rub against each other.
The Japanese maple tree is known to be relatively pest-resistant. Although aphids do love these trees, they do not pose a serious health threat. Still, these chewing insects can cause the foliage to become unsightly. In addition, they secrete a sticky residue that makes quite a mess all over the tree. The sweet smell of the residue (called honeydew) can also attract other insects. Aphids can be controlled by spraying your Japanese red maple tree with an insecticide.