The Arakawa Japanese Maple (Acer palmatum ‘Arakawa’) is an ornamental tree known for its unique, deeply fissured, corky bark, its common name “rough bark.” Originating from Japan, this tree offers year-round visual interest, making it a focal point in the landscape, especially in winter.
Unique Characteristics
The Arakawa Japanese Maple’s bark matures over several years, developing a rough, warty, and deeply fissured appearance, often compared to alligator skin or pine bark. This texture typically begins to show on specimens around 3 to 5 years of age, creating an illusion of great age even on relatively young trees. This provides significant winter interest after leaf drop. The tree forms an upright, broad canopy, reaching an ultimate height of 20 to 25 feet and a width of 15 to 20 feet at maturity.
The Arakawa Japanese Maple’s foliage changes throughout the seasons. Its delicate, palmate leaves, with 5 to 7 lobes, emerge in spring as light green, sometimes bronze-tinged. Leaves maintain a medium green color through summer, occasionally showing bronze-red on new growth. In autumn, foliage transforms into brilliant shades of golden yellow, orange, and striking dark red or fuchsia.
Planting and Site Requirements
Optimal growth requires an appropriate planting site. Arakawa Japanese Maples thrive in partial shade, ideally morning sun with afternoon shade, especially in hotter climates, to protect leaves from scorch. A sheltered position, away from strong winds and late frost pockets, also prevents damage.
Arakawa Japanese Maples prefer moist, organically rich, well-draining soil with a slightly acidic to neutral pH (5.0-7.0). Amend heavy clay soils to improve drainage, as the tree is susceptible to root rot in waterlogged conditions.
When planting, dig a hole two to three times wider than the root ball but not as deep, ensuring the top of the root ball sits slightly above the surrounding soil line. Backfill with amended soil and water thoroughly to settle it around the roots.
Ongoing Care
Consistent moisture is important for Arakawa Japanese Maples. Deep watering is recommended, allowing the top inch or two of soil to dry out slightly between waterings to prevent waterlogging. Apply a 2 to 4-inch layer of organic mulch around the base of the tree to retain moisture, regulate temperature, and suppress weeds.
Fertilization is generally minimal for established Arakawa Japanese Maples. If needed, apply a balanced fertilizer for acid-loving plants in early spring before new growth emerges. Avoid over-fertilizing, especially with high-nitrogen formulas, as this promotes soft growth susceptible to pests.
Pruning is best done in late winter or early spring, before sap begins to run. Remove dead, damaged, or crossing branches and thin crowded areas to improve air circulation and reveal the distinctive bark.
Winter protection is minimal for Arakawa Japanese Maples in their recommended hardiness zones (USDA Zones 5-9). Established trees in the ground typically do not require covering. However, monitoring soil moisture during winter is important; provide water during prolonged dry spells. In colder regions, especially for young trees or those in containers, mulching protects the root system from extreme cold. Protecting newly leafed-out trees from late spring frosts is advisable, as new growth is vulnerable to damage.
Troubleshooting Common Problems
While generally robust, Arakawa Japanese Maples can encounter several issues. Leaf scorch is a common environmental stress, appearing as browning or yellowing along leaf margins or between veins, often caused by insufficient water, excessive sun exposure, or strong winds. Adequate watering and afternoon shade can mitigate this. Wilting or drooping leaves signal either underwatering or overwatering; soggy soil leads to root rot.
Pests such as aphids, scale insects, and spider mites affect Arakawa Japanese Maples. Aphids are small, sap-feeding insects leaving sticky honeydew. Scale insects appear as tiny bumps on stems and leaves, feeding on sap. Regularly inspect for these pests and treat with horticultural oil or insecticidal soap to manage infestations.
Fungal diseases, including verticillium wilt, powdery mildew, and leaf spot, occur. Verticillium wilt is a soil-borne fungus causing wilting and dieback of branches. Powdery mildew manifests as white, powdery growth on leaves; leaf spot causes discolored patches. Proper air circulation through good spacing, pruning, and sanitation prevents these fungal issues.