Japanese Maple

Japanese maple is the tree that Western Washington does better than almost anywhere else in North America. The maritime climate, mild winters, cool summers, reliable moisture, is close enough to the species' native range in the mountain forests of Japan, China, and Korea that Japanese maples grow here with an ease that gardeners in the Midwest or Southeast would find infuriating. You already know what it looks like: the layered branching, the finely cut foliage, the fall color that runs from gold through orange to scarlet depending on the cultivar. What you may not know is that the genus carries one of the longest susceptibility lists in the knowledge base, nineteen documented diseases and fifteen pests.

Seven cultivars anchor the regional trade. 'Bloodgood' is the standard upright red-leaf form, reaching fifteen to twenty feet. 'Sango Kaku', coralbark maple, delivers coral-red winter bark that lights up in January. 'Shaina' and 'Sharp's Pygmy' stay compact enough for containers and small gardens at six and four feet respectively. 'Pixie' reaches ten feet. 'Beni Komachi' and 'Shindeshojo' are selected for intense spring color. Across all cultivars, site selection matters more than variety selection. Part shade with morning sun produces the best results in most of Western Washington, full afternoon sun in July will scorch the fine foliage, especially on dissected-leaf varieties. Well-drained soil is essential, and Verticillium wilt in the soil is the primary threat to all maples. The soilborne fungus persists indefinitely and there is no chemical control.