Japanese maple (Acer palmatum) is a small, slow-growing tree, and most of what it needs comes down to the spot you put it in. Give it dappled shade, soil that stays evenly moist but drains well, and shelter from drying wind, and it needs very little else. Most problems people see, such as crispy brown leaf edges, start with too much sun, wind or drought.

Table of Contents

The short answer: plant a Japanese maple in partial or dappled shade in moist, well-drained soil, out of drying winds. Water deeply during dry spells, especially in the first years, and keep 3 to 4 inches of mulch over the root zone, pulled back from the trunk. Prune lightly, and avoid heavy pruning in spring when maples bleed sap. Fertilize only if a soil test shows a need.

Start with the right site

Both The Morton Arboretum and NC State Extension describe the same preferred site. Morton lists partial sun or shade (4 to 6 hours of light a day), acid soil and moist, well-drained soil, and says Japanese maples do best in a partly shaded site with a consistent supply of water. NC State recommends dappled shade and evenly moist, well-drained soil, and says to protect the tree from drying winds.

The reason is the leaves. NC State notes that young leaves are sensitive to frost and are not drought tolerant, and that the tree may suffer leaf scorch with excess sun, wind or drought. Morton adds that dry soils can lead to leaf scorch. A spot on the east side of a house, or under the high canopy of larger trees, often fits.

Hardiness varies. Morton lists zones 5 to 8, and NC State lists 5a to 8b. Morton cautions that not all cultivars are fully hardy in zone 5 and some may need winter protection there.

Know how big your cultivar gets

Japanese maple can be a large shrub or a small tree. Morton gives a mature height of 15 to 25 feet and a width of 15 to 35 feet for the species, and NC State gives 15 to 25 feet tall and 10 to 25 feet wide. Cultivars vary a lot. Some examples from The Morton Arboretum:

Cultivar	Form	Size given by Morton
‘Bloodgood’	Rounded, purple-red leaves	About 18 feet high and wide
‘Crimson Queen’	Weeping, dissected leaves	About 6 feet high, 8 feet wide
‘Tamukeyama’	Weeping, dissected leaves	About 10 feet high, 12 feet wide
‘Viridis’	Weeping, green dissected leaves	8 to 10 feet high, 8 feet wide
‘Shishigashira’ (Lion’s Head)	Vase-shaped, crinkled leaves	About 15 feet high, 10 feet wide

Check the tag for the expected size before you plant, so you do not have to keep cutting it back. For more on sizes, see how big a Japanese maple grows.

Watering

Water matters most. The Morton Arboretum’s watering guidance says to water deeply rather than lightly and often, so that water soaks at least five to six inches into the soil; an inch of water applied at one time can reach that far. Check the soil rather than watering on a fixed schedule, and water newly planted trees on both the root ball and the surrounding soil.

Morton also notes that trees, especially newly planted ones, need ample water going into winter, so keep watering in fall as long as the soil is not frozen and can accept water.

Because Japanese maple is moderately sensitive to drought (Morton) and scorches in dry soil, a young tree in its first few summers needs the most attention. Feel the soil a few inches down before watering; if it is still moist, wait.

Mulch

A layer of organic mulch keeps the root zone cool and moist, which suits this tree well. The Morton Arboretum recommends mulch 3 to 4 inches deep under trees for medium to coarse materials, pulled away from the trunk to leave a “donut hole.” On a young tree, it suggests extending the mulched area to the drip line of the branches. Do not pile mulch against the bark.

Pruning

Japanese maples need little pruning if they are planted where they have room. Remove dead, broken or rubbing branches, and thin lightly to show off the branch structure.

Timing matters for maples. The Morton Arboretum’s plant page says to avoid pruning maples in spring because they are bleeders and lose a large amount of sap. Iowa State University Extension says the sap flowing from a cut maple in late winter or early spring is unsightly but does not harm the tree, and the wounds do not need sealing. Morton’s general pruning guidance is that most deciduous trees are best pruned from late fall, once dormant, to very early spring, and that pruning can be extended into very late spring or very early summer, when it is harder to see the structure and pests are more active.

Keep cuts small and make them just outside the branch collar. Most cultivars are grafted, NC State notes, so remove any shoots that come from below the graft, since they grow from the rootstock and will not look like the cultivar. For more on timing, see the best month to trim a maple and whether you can trim a maple in summer.

Fertilizer

Most established Japanese maples do not need regular feeding. The Morton Arboretum recommends adding nutrients only if soil or leaf tests show a deficiency, and warns that too much nitrogen produces soft growth. Morton also prefers acid soil for this tree. If a soil test shows high pH, that is worth knowing before you buy any product.

Common problems

Morton lists anthracnose, verticillium wilt and leaf scorch as the main problems, with scorch most likely on dry, sunny sites. NC State adds occasional aphids, scale, leafrollers and leafhoppers, and frost damage, especially from late spring frosts. NC State also notes that the species self-seeds easily and is listed as invasive in Virginia and Washington, DC, so pull unwanted seedlings.

What you see	Likely cause	What to do
Brown, crispy leaf edges in summer	Leaf scorch from sun, wind or dry soil	Water deeply, mulch, consider a shadier spot
New leaves blackened after a cold night	Late frost	Usually recovers; wait for new growth before pruning
Leaves wilting on one branch or side	Possibly verticillium wilt	Have it diagnosed; see why a maple may be dying
Spots and blotches in a wet spring	Anthracnose	Rake fallen leaves; usually cosmetic

If you need to move a young tree to a better spot, read how to transplant a Japanese maple first.

Key takeaways

Plant in dappled or partial shade, in moist, well-drained, preferably acid soil, out of drying winds.
Water deeply during dry spells and into fall; keep 3 to 4 inches of mulch over the roots, away from the trunk.
Prune lightly; maples bleed sap in late winter and spring, which looks alarming but does not harm them.
Fertilize only if a soil test shows a need.
Leaf scorch is the most common problem and usually means the site is too sunny, windy or dry.

Sources

Japanese maple, The Morton Arboretum
Acer palmatum, North Carolina Extension Gardener Plant Toolbox
Watering Trees and Shrubs, The Morton Arboretum
How to Mulch Trees and Shrubs, The Morton Arboretum
Pruning Trees, The Morton Arboretum
Sap flowing from a pruning cut on my maple tree. Should I be concerned?, Iowa State University Extension
How and When to Use Fertilizer on Plants, The Morton Arboretum

Top photo: Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, via Wikimedia Commons

Japanese Maple Care: Site, Water, Mulch and Pruning