The Moonglow Japanese Maple is a distinctive and captivating choice for ornamental beauty in various landscape designs. Known for its radiant appearance, this cultivar offers a visual spectacle throughout the seasons, hinting at the luminous quality its name suggests.
Moonglow Japanese Maple Characteristics
The Moonglow Japanese Maple (Acer shirasawanum ‘Aureum’) is celebrated for its dynamic seasonal foliage. In spring, its fan-shaped leaves emerge bright yellow, transitioning to a softer yellow-green in summer. Filtered light intensifies this vibrant color, creating a luminous effect. By autumn, the leaves ignite with tangerine, golden-orange, and red tones, offering a brilliant fall display.
This Japanese maple grows upright, maturing into a small to medium-sized tree, reaching 8 to 10 feet tall and about 8 feet wide over 20 years. Its slow growth rate, around one foot per year, makes it suitable for various landscape placements. It thrives in USDA hardiness zones 5 through 8.
Planting and Site Selection
Successful establishment of a Moonglow Japanese Maple requires careful site selection. These trees flourish with morning sun and protection from intense afternoon sun, which prevents leaf scorch. An eastern-facing spot or dappled shade from larger deciduous trees offers ideal protection. Strong wind protection is also beneficial, as delicate foliage is susceptible to damage.
Japanese maples prefer well-drained, slightly acidic soil (pH 6.0-7.0). Amending heavy clay soils with organic matter improves drainage, crucial as these trees do not tolerate consistently wet roots. When planting, dig a hole two to three times wider than the root ball, but only as deep. This prevents planting too deeply, which can impede growth and lead to root issues.
Place the tree so the top of the root ball is at or slightly above ground level. Backfill with amended soil, gently firming to remove air pockets. An initial deep watering settles the soil and provides essential moisture. Apply a 2 to 4-inch layer of organic mulch, like pine bark or straw, around the base to retain moisture and regulate temperature, keeping it a few inches from the trunk to prevent rot.
Ongoing Care
Consistent care ensures the long-term health of your Moonglow Japanese Maple. Proper watering is important, especially during dry periods and for newly established trees. Deep, infrequent watering encourages a robust, deep root system, making it more resilient to drought. Check soil moisture by hand; if the top inch feels dry, water thoroughly.
Fertilize cautiously, as Japanese maples are not heavy feeders. Over-fertilizing, especially with high-nitrogen formulas, can lead to weak, leggy growth and damage. Apply a slow-release, granular fertilizer, such as a balanced 10-10-10, in early spring as the tree leafs out. Avoid fertilizing after late spring (around May or June) to allow the tree to prepare for dormancy and prevent new growth from frost damage.
Prune primarily for shaping, size maintenance, and removing dead or damaged branches. Major structural pruning is best done in late winter while the tree is dormant, before new growth, to minimize stress and allow a clear view of the branching structure. Minor shaping of young trees can be done year-round, but avoid heavy pruning during the growing season. In colder zones (USDA zone 5), apply mulch and ensure adequate moisture before winter to insulate roots. Potted maples in these zones may benefit from moving to a sheltered location, like an unheated garage, to protect roots from freezing.
Common Issues
Even with proper care, Moonglow Japanese Maples can face environmental issues. Leaf scorch, characterized by browning or crisping leaf edges, is common, often caused by excessive sun, strong winds, or insufficient watering during hot, dry periods. Scorched leaves won’t recover, but adjusting watering and providing afternoon shade prevents further damage. Heat stress can also manifest as wilting or stunted growth, indicating a need for consistent moisture.
Japanese maples are generally resilient to pests, though some can be a concern. Aphids, small soft-bodied insects, feed on plant sap, causing leaves to curl or discolor. A strong water spray often dislodges them; insecticidal soap can be used for severe infestations. Scale insects appear as tiny bumps on branches and leaves, leading to stunted growth. Horticultural oil helps manage these pests.
Fungal diseases are also possible, with Verticillium wilt being a serious concern. This soil-borne fungus causes wilting, yellowing leaves, and branch dieback, sometimes affecting only one side of the tree. There is no cure, so prevention through proper site selection and avoiding planting in previously infected soil is important. Other fungal issues like anthracnose and powdery mildew are typically cosmetic, causing spots or a powdery coating on leaves, and can be managed with good air circulation and sanitation.