Japanese Maple: Invasive or Not?

Question: I heard on TV that the Japanese maple tree is considered an “invasive” plant. I have one of these trees in my yard. Should I remove it?

Great question! The topic of invasive plants can be a tricky one. First, let’s start with a definition. The U.S. Department of Agriculture defines “invasive species” as an alien species whose introduction does or is likely to cause economic harm, environmental harm, or is a risk to human health.

In other words, they are plants that may be from one country and introduced into another or simply plants that have been introduced in habitats where they have not grown in the past. They may cause issues by dominating a region, wilderness area, or a particular habitat. Often these introduced species do not have a natural predator, typically an insect, in the new habitat and can grow much faster than the native species around it. Often these plants are brought to the new area on purpose, as kudzu was for erosion control and cattle fodder, or as an ornamental by a nursery, such as English ivy. However, plants can be brought in by birds, other wildlife, or by water.

Not all plants from other areas are necessarily going to become invasive, but the few that do can replace native plants and unbalance the native ecosystem. For example, wildlife has evolved to use native plants for food and shelter. When invasive plants replace the native plants, wildlife can suffer. The loss of milkweed in our area resulted in a decrease of Monarch butterflies. Their caterpillars feed only on native milkweed. For a list of known invasive plants in Virginia, maintained by the Virginia Department of Conservation & Recreation, visit here.

The Japanese maple is prized for its beauty in the landscape – these trees are small, provide colorful foliage, and create a nice canopy. Currently, the Virginia Department of Conservation & Recreation does not list the Japanese maple as an invasive species.

You likely heard about this on the TV because certain organizations specifically devoted to healthy landscapes and environmentally friendly gardening and horticulture address the “invasive” characteristics of this tree. Japanese maples can reproduce easily because they produce a lot of seeds. As a result, Japanese maple may reseed near forests and replace native plants. Although it has yet to have a major negative impact in Virginia, certain areas are experiencing issues with the Japanese maple – for example, the eastern United States, Hawaii, Canada, and New Zealand. It is listed as a “problem plant” by the Mid-Atlantic Exotic Pest Plant Council and reported as invasive in Rock Creek National Park in Washington D.C. by the Master Gardeners of Northern Virginia.

If you want to be really prudent and avoid long-term (100 year+) impact, then consider cutting down your Japanese maple. However, at present, this tree has a relatively low impact compared to other invasive trees, such as the Tree of Heaven. We recommend keeping an eye out for saplings of Japanese maples in forested areas. The best thing to do is to plant a native tree next time you plant a tree. Suggested varieties include the common elderberry, eastern redbud, flowering dogwood, fringetree, red elderberry or witch hazel. For a list of common native Virginia trees, from the Department of Forestry, click here.

Resources

“What Are Invasive Species?”, United States Department of Agriculture, National Invasive Species Information Center

“Mid-Atlantic Exotic Pest Plant Council Plant List”, National Park Service

“Tried and True Native Plants to Replace Invasive Plants, Invasive Plant: Japanese Maple (Acer Palmatum)”, Master Gardeners of Northern Virginia

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