Japanese maple
Sources last read 14 September 2026.
Middling It gives warning, with time to act.
Also called Japanese Maple Cultivars and smooth Japanese maple.
Toxicity is partly unassessed
- Not assessed for cats. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
- Not assessed for dogs. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
- Not assessed for people. RHS publishes no harm statement for this plant. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
What the sources say about its care
- Light
- Full sun, Partial shadeRHS · read 13 September 2026
- Water
- Moist but well-drainedRHS · read 13 September 2026
- Humidity
No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.
ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%Penn State Extension · read 13 September 2026- Temperature
How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.
H6 — -20 to -15°C -20 to -15 °CRHS · read 13 September 2026- Soil
- Chalk, Clay, Loam, Sand; pH Acid or NeutralRHS · read 13 September 2026
- Toxic to cats
- Not on the ASPCA list. That is not a finding of safety.ASPCA · read 13 September 2026
- Toxic to dogs
- Not on the ASPCA list. That is not a finding of safety.ASPCA · read 13 September 2026
- Harmful to people
- No statement of harm to people is published for this plant; that absence is not evidence it is safe.RHS · read 13 September 2026
How it usually goes wrong
- Dry, curled edges on leaves near a heater
A yellow halo sits just inside the brown edge on the Japanese maple, and new leaves often come in already tipped with brown during the heating season.
The edges fail first because they are the end of the plumbing. Penn State Extension cites 30% to 60% as the recommended indoor range, and winter heating regularly takes a room under it. That applies while it is grown indoors; its RHS rating of H6 describes a plant that also grows outside, where the air is seldom that dry.
Telling it apart: Whether the soil is dry too. Crisp edges with damp soil point at the air; with dry soil, at the watering.
Penn State ExtensionDiagnose brown tips and edges on this Japanese maple- Scorched patches on the side facing the wind
Marks on the Japanese maple are concentrated on the windward side: torn edges, dry brown patches and leaves rubbed against each other.
RHS lists it for a sheltered position. Wind pulls water from the leaf faster than roots replace it, and it bruises the tissue it strikes, so a plant grown out in the open is marked on its windward side.
Telling it apart: Whether the sheltered side is clean. Wind marks only what it reaches.
RHSDiagnose spots on the leaves on this Japanese maple- Whitened areas where the sun falls longest
Scorched leaves on the Japanese maple turn from pale to brown and brittle, and the damage stops where the shade of another leaf fell across it.
Its source names full sun or partial shade, so the light itself is not the fault. Foliage that formed in a dimmer room is thinner than foliage grown in sun, and the side turned suddenly to strong light bleaches before it can adjust.
Telling it apart: Which side. Damage confined to the lit side is light; damage spread evenly is not.
RHSDiagnose leaf drop on this Japanese maple- Yellowing that begins at the leaves deepest inside the canopy
A sour smell from the compost is common on a Japanese maple, and the leaves deepest inside the canopy come away when pulled. The surface may look dry while everything beneath it is not.
Its source describes soil that is moist but well-drained. Roots held below that are short of air, and roots short of air stop moving water, so the canopy wilts in a wet pot.
Telling it apart: Whether new growth is affected too. Root damage shows up everywhere at once; ordinary leaf loss shows only in the oldest leaves.
RHSDiagnose yellowing leaves on this Japanese maple
Not sure which it is? Ask the diagnosis questions for Japanese maple.
Routine care
- Watering
- In summer, water when needed.RHS · read 13 September 2026
- Propagation
- By grafting.NC State Extension · read 13 September 2026Increase by grafting or softwood cuttings.RHS · read 13 September 2026
- Pests and diseases
- Can be troubled by Japanese maple scale (Lopholeucaspis japonica; Hemiptera: Diaspididae), aphids, Japanese maple leafhopper and other maple insect pests. Diseases: common maple diseases.NC State Extension · read 13 September 2026Can be troubled by caterpillars, horse chestnut scale, aphids and Acer gall mite. Diseases: honey fungus, acer leaf scorch and Verticillium wilt can occur.RHS · read 13 September 2026
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Photographs
About the plant
Acer palmatum, commonly known as Japanese maple, palmate maple, or smooth Japanese maple, is a species of woody plant native to Korea, Japan, China, eastern Mongolia, and far eastern Russia. Many different cultivars of this maple have been selected and they are grown worldwide for their large variety of attractive forms, leaf shapes, and spectacular colors.
From Wikipedia, CC BY-SA 4.0 · read 13 September 2026
- Native range
- SW. Korea, C. & S. JapanWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026Asia: Japan, China, Korea, eastern Mongolia, southeastern RussiaNC State Extension · read 13 September 2026Japan, C China, KoreaRHS · read 13 September 2026
- Climate
- temperateWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026
- Growth form
- Perennial, Shrub, Tree; habit broad, dense, rounded, spreadingNC State Extension · read 13 September 2026Bushy (deciduous)RHS · read 13 September 2026
- Size
- Height 180–300 in; width 120–300 inNC State Extension · read 13 September 2026Height 4-8 metres; spread 4-8 metres after 10–20 yearsRHS · read 13 September 2026
- Flowering
- Flowers gold/yellow, purple/lavender, red/burgundy; blooms in springNC State Extension · read 13 September 2026Flowers red in springRHS · read 13 September 2026
Plants with similar care
AvocadoDry scorched spots after a move into a sunnier spot
Chinese banyanFaded, yellow-white areas on the sunny side of the canopy
Coffee plantLeaf tips go crisp and brown
Crape myrtleCrisp margins that appear in winter
Norfolk Island pineBleached patches on the side facing the glass
OliveA thin dry rim that crumbles between the fingers
Sources
- ASPCA · read 13 September 2026
- Kew WCVP · read 13 September 2026
- NC State Extension · read 13 September 2026
- Penn State Extension · read 13 September 2026
- RHS · read 13 September 2026
- Wikipedia · read 13 September 2026
What this does not cover
The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.
Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.
If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.