Tree or large shrub
How to grow a Japanese maple (acer)
Acer palmatum cultivars
A Japanese maple succeeds or fails on shelter. Plant it between October and March in dappled shade, out of cold wind and hot afternoon sun, in moist but free-draining soil that is neutral to slightly acid. Set the rootball level with the surface, mulch every spring and keep the roots evenly moist through summer. The lacy dissectum types are the most easily scorched and the best suited to pots. Prune only if you must, and only when fully dormant.
- Hardiness
- Fully hardy (new leaves frost-prone)
- Position
- Light, dappled shade, sheltered
- Soil
- Humus-rich, moisture-retentive, free-draining, slightly acid
- Ideal pH
- 5.5 to 6.5
- Water
- Moderate to high in pots; never dry in summer
- Feeding
- Light feeder
Sowing and planting a Japanese maple (acer)
WhenPlant Oct to Mar; autumn colour Oct to Nov; prune only in Dec to Jan if needed
Starting off
Plant pot-grown stock Oct to Mar in a spot sheltered from east and north winds and hot afternoon sun; trees are grafted, so plant with the graft union above soil. Named cultivars must be grafted (Feb, under cover) or taken as softwood cuttings in Jun with bottom heat at 20°C, which is unreliable; the species comes easily from seed sown fresh in Oct outdoors, germinating in Apr. Repot container trees every 2 to 3 years in Mar, root-pruning lightly.
Spacing and planting
Upright cultivars ('Bloodgood', 'Osakazuki') reach 4 to 6 m tall by 4 m wide in 20 years; dissectum types ('Garnet', 'Inaba-shidare') make a 1.5 to 2 m by 2 m mound; 'Sango-kaku' 6 m by 4 m. Plant 2 to 3 m from other plants and 3 m from buildings, in a wide hole only as deep as the rootball with the top level with the surface, never deeper. Dissectum and dwarf types are superb in a 45 to 60 cm pot of loam-based ericaceous compost with 20 per cent grit.
Varieties worth growing
- 'Bloodgood'
- The standard purple upright: deep red-purple leaves that hold their colour all summer, then turn scarlet. Tougher in sun and wind than most. 4 to 5 m in time.
- 'Osakazuki'
- Plain green in summer and the most dependable autumn colour of any acer, a clear burning scarlet. Tolerates more sun than the purple and cut-leaved forms.
- 'Sango-kaku'
- The coral-bark maple: young stems glow coral red all winter, leaves turn soft yellow in autumn. Upright and narrow when young.
- 'Garnet'
- Red-purple dissectum forming a low weeping mound about 1.5 m high; the classic acer for a large pot in a sheltered courtyard.
- 'Katsura'
- Small upright tree whose leaves open orange-yellow in April, turn green for summer and go orange again in autumn. Opens early, so keep it out of frost pockets.
A Japanese maple (acer) month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Last chance for any pruning: dead, crossing or badly placed shoots only.
- February
Plant in mild spells. Do not prune from now on.
- March
Plant. Light feed. Repot or top-dress container trees before the buds break.
- April
Leaves open. Fleece on frost nights. Mulch 5 cm with leaf mould or composted bark, clear of the trunk.
- May
Water new trees weekly. Rub off aphids. Remove plain green shoots from below the graft.
- June
Start regular watering of pots; never let them dry out.
- July
Water deeply once a week in dry weather. Shade pots from afternoon sun.
- August
Keep watering. Scorched leaf edges now are cosmetic; do not feed.
- September
Ease off watering as nights cool. Nematodes on pots.
- October
Autumn colour. Plant from now. Sow seed of the species fresh, outdoors.
- November
Leaf fall. Plant. Pruning window opens once all the leaves are down.
- December
Prune if needed. Raise pots on feet and wrap them in a hard frost.
Feeding a Japanese maple (acer)
A light feeder. One half-rate balanced feed in March and a spring mulch is enough; a tree in good soil can go without. Feeding a scorched tree in summer makes the scorch worse.
Low, a light feed; rich feeding spoils the delicate habit.
Feeding plan
Planting
5 g per litre of rootball dusted onto the roots so it touches them: 50 g for a tree from a 10 litre pot. Once only.
March, in the ground
50 g/m², half the label rate, scattered under the canopy and watered in: about 150 g for a tree 2 m across (3 m²). Skip it if last year's shoots were longer than 20 cm.
April
Leaf mould or composted bark
A 5 cm mulch out to the edge of the canopy, kept off the trunk.
March, pots
2 g per litre of compost scattered on the surface and watered in, the bottom of the label range: 80 g for a 45 cm pot (about 40 litres). Once a year.
May to July, pots, every 3 weeks
1 g per litre of water as a drench. Stop at the end of July so the wood ripens before winter.
Signs to watch
Brown, crisped leaf edges and tips in Jul to Aug
Leaf scorch from wind, hot sun or drought at the root, not a deficiency, and worst on dissectum and variegated types
More shelter, 5 cm mulch, water 10 litres weekly, no feeding, which makes it worse
Yellow leaves with green veins on chalk or in a pot watered with hard mains
Lime-induced chlorosis
Rainwater, sulphur chips, ericaceous feed with
Pests, diseases and problems
One branch or one side of the tree wilts suddenly in summer and dies; cut wood shows dark streaks under the bark
Verticillium wilt, a soil-borne fungus
No cure. Cut affected branches back to clean wood, cleaning the saw between cuts, then water and mulch to keep the tree growing. If it dies, do not plant another acer in the same soil.
New leaves blacken and shrivel in April or May
Late frost or cold wind on soft growth
Fleece small trees on frost nights and move pots against a wall. The tree releafs from dormant buds within a few weeks; do not feed to hurry it.
Shoot tips sticky and curled in May and June, with clusters of small insects
Aphids on soft new growth
Rub them off or wash them off with a jet of water. Ladybirds and blue tits clear most colonies by midsummer; heavy feeding makes it worse.
A pot-grown tree wilts and fails to leaf up properly, with white grubs in the compost
Vine weevil grubs eating the roots
Nematodes watered in during late August or September and again in April. Check the rootball whenever you repot.
Small coral-pink pustules on dead twigs
Coral spot, a fungus that enters through dead wood and old pruning snags
Cut out dead twigs to healthy wood in dry weather and bin them. Dieback of fine twigs is common on acers after a hard winter and is the usual way in.
Cuts weep sap for days after pruning
Pruning in late winter or spring, when the sap is rising
Prune only between November and January, when the tree is fully dormant, and keep cuts small. A bleeding cut is best left alone to stop on its own.
Pruning
Pruning and care
Cut out any vigorous plain-leaved shoots from the rootstock below the graft. Mulch 5 cm with leaf mould or composted bark each Apr, keeping it off the trunk. Protect new leaves from a late Apr frost with fleece; move pots out of wind.
Good to knowShelter from cold winds and hot midday sun, which scorch the leaves; superb in a pot of loam-based ericaceous compost.
Growing a Japanese maple (acer) in pots
Japanese maples are among the best small trees for pots, and the dissectum types are happier there than in an exposed border. Use a 45 to 60 cm frost-proof pot, a loam-based ericaceous or loam-based general compost with a fifth grit, and stand it out of the wind in light shade. Watering is the whole job: the compost must stay evenly moist from April to September, which can mean daily in July, with rainwater if your mains is hard. Repot every two to three years in March, trimming the outer roots lightly, and wrap the pot in hard frost because the roots are less hardy than the top.
A Japanese maple (acer): common questions
Why are the leaves on my acer turning brown and crispy?
It is leaf scorch, caused by wind, hot sun or dry roots, and it is not a disease or a shortage of feed. Move pot-grown trees to a sheltered, lightly shaded spot, mulch, and water regularly. The tree leafs up normally the next spring.
Can I grow a Japanese maple in full sun?
Green-leaved upright types such as 'Osakazuki' cope with full sun if the soil stays moist and the site is out of the wind. Purple, variegated and cut-leaved dissectum forms scorch in hot afternoon sun and are better in dappled or morning-only light.
When is the best time to prune a Japanese maple?
Between November and January, when the tree is fully dormant. Acers bleed sap if cut in late winter or spring. Most never need pruning beyond removing dead twigs and any plain green shoots from below the graft.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.