Tree · Sapindaceae
Tamukeyama Japanese Maple
Acer palmatum
A weeping laceleaf cultivar prized for finely dissected purple-red foliage that colors from spring to a scarlet fall.
Partial shade
Every 3–7 days
USDA 5–8
6–8 ft · 1.8–2.4 m
Overview
Acer palmatum 'Tamukeyama' is a small weeping maple grown for its foliage rather than its bloom. Its leaves are dissected to the point that the blade reduces to fine, thread-like lobes, a laceleaf form, and they emerge and hold a saturated purple-red. Mature dimensions run to 6 to 8 feet (183 to 244 cm) tall with a spread that exceeds the height, producing the low, cascading, mounded canopy typical of dissectum cultivars.
What distinguishes this cultivar from the broader run of dissectum maples is its constitution. It retains pigment through high summer temperatures that push less-tolerant selections toward a muddy bronze, and it withstands direct sun more reliably than most. Growth is slow, which keeps the plant in proportion for many seasons, and the same finely cut leaves that stay red all summer develop scarlet to bright red autumn color before they drop.
Like the species as a whole, it responds to placement more than to any single input. Sited in dappled light with consistent soil moisture and protection from intense afternoon sun, the fine-lobed leaves stay intact and well colored. Placed in hot, exposed sun with a drying root zone, the fine margins desiccate and brown, which is the disorder growers encounter most often with this tree.
Care
The short version: partial shade shielded from hot afternoon sun, an evenly moist and slightly acidic root zone, mulch to moderate soil temperature and water loss, and pruning confined to the dormant season for light shaping.
Light
Provide dappled or partial shade, screening the plant from the hottest afternoon sun. Full sun is tolerated in cooler climates and where the soil stays moist, because transpiration can then keep pace with the light load. In hot, dry exposures that balance breaks down and the fine leaves scorch.
Water
Maintain evenly moist soil, watering on the order of every 3 to 7 days and more frequently during heat. The finely divided foliage has little buffer against water stress, so a dry root zone quickly shows as scorch. A mulch layer conserves soil moisture and moderates root-zone temperature, both of which reduce that stress.
Soil
Grow it in moist, organically rich, well-drained loam held slightly acidic, at a pH of 5.5 to 6.5. Above that range iron becomes less available to the roots and the leaves develop chlorosis, so incorporate organic matter and avoid alkaline, limy soils.
Temperature
Cold hardiness spans roughly -20°F to 95°F (-29°C to 35°C), corresponding to USDA zones 5 through 8. The plant tolerates severe winter cold without injury. Stress instead concentrates at the upper end, where high air temperature compounds the solar load on the leaves.
Humidity
Ambient humidity is not a limiting factor, so no target is needed. The variables that govern leaf condition are root moisture and exposure to drying wind, both of which affect water balance far more than the surrounding air.
Feeding
Apply a balanced slow-release fertilizer in early spring, once per season. Nutrient demand is low, and over-fertilizing forces soft, rapid growth whose thin tissue scorches more readily, so restraint serves the plant better than heavy feeding.
Pruning
Pruning needs are minimal, limited to light shaping that preserves the cascading habit. Carry it out from late fall through midwinter during dormancy, since cuts made in spring or summer bleed sap heavily from the open wounds.
Repotting
Repot container specimens every 2 to 3 years, working in late winter while the tree is dormant and root disturbance is best tolerated. Circling roots, stalled growth, and water that drains straight through signal that the root mass has outgrown the pot.
Size & spacing
Mature height reaches 6 to 8 feet (183 to 244 cm), with a spread of 8 to 12 feet (2.4 to 3.7 m) that exceeds the height and produces the weeping profile. Slow growth means the plant occupies that footprint only gradually, staying in scale for years.
When to plant
As a long-lived woody plant, this maple is set once and left in place, so establishment conditions outweigh the calendar. Plant in spring or fall after the risk of hard frost is gone, when soil temperatures are moderate and the root system can extend and establish before the demands of summer heat or hard winter cold arrive.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall, after frost danger has passed.
- Harvest: Insignificant reddish-purple flowers in April; grown for foliage with scarlet to bright red fall color.
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
The majority of problems on a Japanese maple present in the foliage, and marginal scorch in summer is by a wide margin the most frequent. Most resolve once you identify whether the cause is the exposure of the site or the moisture at the roots. Compare the symptoms below, then correct the placement or irrigation before the injury advances.
One-sided dieback with wilting, chlorotic foliage
Dieback and yellowing confined to one side of the canopy point to verticillium wilt, a soil-borne fungus that occludes the water-conducting xylem. Peel bark from a symptomatic branch to check for dark streaking that follows the grain, and submit tissue to a diagnostic lab to separate it from Fusarium. No cure exists, so excise dead wood, sustain vigor through irrigation and slow-release feeding, and avoid replanting a susceptible species in the infested soil.
Fix:
- Prune out dead and dying wood
- Maintain vigor with proper irrigation and slow-release fertilizer
- Consult a certified arborist for hazard assessment
- Remove severely affected plants and avoid replanting susceptible species in infested soil
Marginal leaf scorch in hot, dry conditions
Browned, brittle margins are leaf scorch, appearing first on the foliage most exposed to sun and wind. The dissected leaf loses water faster than the roots can supply it once the soil dries or afternoon radiation peaks, and the thin margins dry first. Reduce the load with afternoon shade, hold the root zone evenly moist, and mulch to buffer both moisture and soil temperature.
Fix:
- Provide afternoon shade
- Keep soil consistently moist
- Apply mulch to retain moisture and cool roots
- Shelter from drying winds
Honeydew, sooty mold, and deformed new growth
Sticky residue is honeydew excreted by aphids or scale as they feed on phloem sap, and the black film is sooty mold colonizing those sugars. Confirm by examining leaf undersides and stems for the insects. A forceful water spray dislodges aphids, and horticultural oil or insecticidal soap manages heavier populations without harming the tree.
Fix:
- Hose off aphids with a strong stream of water
- Treat heavy infestations with horticultural oil or insecticidal soap
- Encourage beneficial predators
Toxicity
For pet and livestock owners the record is reassuring: Acer palmatum carries no recognized toxicity. It does not appear on ASPCA toxic-plant lists, and the equine red blood cell toxicosis linked to maples is confined to red and silver maple, not this species. It can be planted around cats, dogs, horses, and other animals without concern.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
Acer palmatum is absent from the ASPCA toxic list, so cats face no toxic risk from it. Ingesting a small amount of leaf is inconsequential, though a large volume of any plant matter can provoke transient drooling or gastrointestinal upset.
Dogs Safe
The species is non-toxic to dogs, containing no compound that would harm them. The realistic worst case is mild, self-limiting gastrointestinal upset after a dog consumes a large quantity of leaves.
Horses Safe
The equine maple toxicosis is restricted to red and silver maple, whose wilted leaves lyse red blood cells. Acer palmatum has no association with that syndrome and is regarded as safe around horses.
Rabbits Safe
No toxic principle in this tree threatens rabbits. The foliage is not a natural dietary component, however, so any consumption should stay incidental rather than displacing hay and fresh greens.
Livestock Safe
Goats, sheep, and cattle may graze in the vicinity without hazard, as the plant lacks the maple toxins implicated in equine poisoning.
Birds Safe
The tree presents no toxic threat to birds, which commonly perch and shelter within its canopy.
People Safe
Acer palmatum is not poisonous to humans. No part is cultivated for consumption, but incidental tasting of a leaf carries no toxic consequence.
No special handling required; minor stomach upset is possible if pets chew large amounts of any plant material.
Varieties
Tamukeyama sits within the dissectum group of weeping laceleaf maples, and a handful of related cultivars share nursery space with it. The following are the ones most useful to tell apart.
Tamukeyama
A strong-growing, heat-tolerant dissectum whose deeply cut purple-red leaves retain their pigment into summer before coloring bright red in autumn.
Crimson Queen
A weeping cutleaf selection carrying finely dissected crimson foliage that holds its color through the summer.
Dissectum Atropurpureum
The archetypal red-purple laceleaf, valued for the low, weeping mound it forms.
Seiryu
An atypical upright cutleaf that departs from the mounding red-laceleaf habit and holds green foliage through summer.
How to propagate
Propagation is not a casual undertaking. As a clonal cultivar, Tamukeyama comes true only through grafting, a controlled nursery technique rather than a garden-scale method.
GraftingDemanding
Late winter to early spring while dormant. · 1-2 years for the graft union to establish.
Tamukeyama is a clonal cultivar, so seed and cuttings will not reproduce it true to type. Nurseries graft a scion onto Acer palmatum seedling rootstock during dormancy in late winter to early spring, a technique that demands precise timing and a skilled hand. The union then requires a year or two to callus and knit before the young tree can be planted out.
Myths
Japanese maples are toxic to cats and dogs.
Acer palmatum is not listed by the ASPCA and is non-toxic to cats and dogs. The toxicosis that drives this belief is specific to red maple, a distinct species whose wilted leaves damage equine red blood cells, and that mechanism does not extend to the Japanese maple.
Japanese maples require deep shade.
In practice they perform from full sun to partial shade. What a hot climate actually demands is afternoon shade combined with steady soil moisture to protect the fine leaves from scorch, not the deep shade the myth prescribes.