Why Is a Japanese Maple Bloodgood Losing Its Leaves?

The Bloodgood Japanese maple tree is one of many cultivars of Acer palmatum, a tree that typically grows to a height and width of no more than 20 feet. Because of its minimal size, the Bloodgood is considered ideal for backyard or landscape use, especially in congested areas. The variety is renowned for its striking red leaves that remain that color through summer and fall. But several different plights can cause the tree to lose those signature leaves.

A Bloodgood Japanese maple tree losing its leaves could be suffering from a potentially deadly case of verticillium wilt, a condition caused by the fungus Verticillium labarum. The disease resides in soil surrounding the tree, first invading the root system and then spreading through the trunk to branches and leaves. As verticillium wilt progresses, the foliage loses much of its color and vitality. "The leaves then begin to drop without wilting, starting at the bases of affected branches and progressing upward," advises the North Dakota State University Department of Agriculture. In some cases, symptoms may display on only one side of the tree, although the entire Japanese maple may be affected.

Japanese maples are more prone than other small trees to developing leaf scorch, a condition where the tips of the leaves prematurely dry out and brown -- or scorch. This affliction often spreads across the entire leaf and, as the scorch worsens, the tree will begin to defoliate. "Symptoms usually appear after drying winds in conjunction with periods of hot, dry weather. Scorch may also suddenly appear when long periods of wet, cloudy weather are followed abruptly by windy and sunny weather," reports the University of Missouri Extension Service. Not surprisingly, the side of the tree exposed to the environmental damage experiences the most consequence of leaf scorch.

The University of Florida Institute of Food and Agricultural Sciences notes that the tree grows best in USDA Plant Hardiness Zones 5 through 8. Bloodgood Japanese maples forced into other, less-hospitable environments, will likely be weakened and more susceptible to a variety of additional leaf diseases like leaf spots, tar spots, powdery mildew and anthracnose. Insects that enjoy feasting on the foliage of a Japanese maple include Japanese beetles, aphids and scales, while borers do exactly that -- "bore" into the bark of a tree, weakening it and denying overall vitality and nutritional flow to the leaves

A Bloodgood Japanese maple requires well-irrigated, slightly acidic soil with a regular supply of moisture. If the soil is poorly drained -- as a means of avoiding root rot -- plant the tree on a slight mound, never allowing water to puddle around the roots. These measures are vital in ensuring that the roots remain healthy and capable of providing a solid supply of hydration and nutrition to the leaves. Issues like air pollution and root injury, especially in urban areas, are capable of proving inhospitable to a Bloodgood Japanese maple. Exercise special caution when mowing to avoid injuring the roots or bark of the tree. Like most plants, the health of a Japanese maple and its leaves is largely dependent on careful management.