Golden full moon maples (Acer shirasawanum “Aureum”) are slow-growing deciduous trees that mature to a height of 20 feet. Their leaves are yellowish-green in the summer, and develop bright burgundy, orange or red edges in the fall. They are hardy in U.S. Department of Agriculture plant hardiness zones 5 to 9. These are good specimen trees for shady gardens, but they require consistent care, and are susceptible to some diseases and insects.
Things You'll Need
- Wood chip or shredded bark mulch
- Japanese maple fertilizer
- Sharp loppers
- Sharp hand pruners
- Garden hose with spray nozzle
- Toothbrush (optional)
Spread organic mulch, such as wood chips or shredded bark, on the soil around the golden full moon maple. Extend the mulch 3 feet beyond the tree trunk. Pull the mulch back away from the trunk, leaving 3 to 4 inches between the trunk and mulch. Mulch holds in moisture, protects the roots and helps prevent injury to the trunk from lawn mowers, which can lead to crown rot. Maintain the mulch at a depth of 3 to 6 inches. Turn and stir the old mulch every two years, and add more, if necessary.
Water the tree in the morning once or twice per week, depending on how quickly the soil dries. This is not a drought-tolerant tree. Keep the root zone moist, not muddy. Check the soil for dryness around the roots 4 to 6 inches below the soil surface. Water the tree slowly and generously, with the water flowing over the root mass near the trunk, when the soil begins to dry. Do not keep the soil too wet. Overly wet conditions can cause verticillium wilt, root rots or stem cankers.
Give the tree organic fertilizer formulated for Japanese maples with a ratio of 4-8-5 in mid-spring beginning the second year after planting. Sprinkle 1/2 cup of fertilizer over the root zone below the tree canopy drip line and water it into the soil. Do not over-fertilize golden full moon maples. Excessive nitrogen from lawn fertilizers can damage the tree.
Prune golden full moon maples in mid-summer using sharp loppers or hand pruners. Prune off only broken limbs or limbs that are forming narrow, weak crotches right after the tree is planted. Do not remove small limbs sprouting toward the base of the trunk. Prune the tree lightly to neaten it up each year. Do a more extensive pruning every three years. Remove dead branches and limbs that are growing across other limbs, or will grow across other limbs if left on the tree. Prune off lower branches growing near the base of the trunk to maintain a tree form.
Watch for signs of maple anthracnose, a fungal disease that can afflict the tree during cool, damp springs. It will cause tan spots on the leaf veins and a general scorched appearance. Leaf spots can be caused by fungal or bacterial infections. Prune off afflicted branches and foliage, and remove them from the area. Aphids, borers, caterpillars, mites and scale insects may attack golden full moon maples. Control aphids and mites by spraying the tree with a strong spray from the garden hose, paying special attention to the undersides of the leaves. Prune off branches that are heavily infested with scales or caterpillars. Remove remaining caterpillars and scales by hand or with an old toothbrush. Gall sawflies may feed on the leaves, and bore into leaf buds and stems, causing the leaves to turn yellow or brown and fall from the tree in mid-spring. Rake up and destroy the fallen leaves each day.
- Washington State University Clark County Extension: PNW Plants -- Golden Full Moon Maple -- Scientific Name Acer Shirasawanum “Aureum”
- Fine Gardening: Acer Shirasawanum “Aureum” (Golden Full Moon Maple)
- Missouri Botanical Garden: Acer Shirasawanum “Aureum”
- University of California: Publication 8048 -- Fruit Trees -- Planting and Care of Young Trees
- Mendocino Maples Nursery: Caring for Maples
- Missouri Botanical Garden: Root, Stem, Crown, and Collar Rot
- Missouri Botanical Garden: Cankers, Diebacks, and Wilts
- Missouri Botanical Garden: Anthracnose of Trees
- Missouri Botanical Garden: Leaf Spot Diseases of Shade Trees and Ornamentals