Common Name: Japanese Maple

General Information

Acer palmatum is a deciduous shrub or small tree with a spreading crown; it can grow up to 15 metres tall in the wild but is generally smaller in cultivation. The bole can be up to 70cm in diameter[].
The tree is sometimes harvested from the wild for local use as a food. A very ornamental tree, it is widely grown in gardens, there are many cultivars.

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - Japan

Habitat

Woods and thickets in a wide range of soils and exposures in lowland and mountains to 3000 metres in C. and S. Japan[, ].

Properties

Edibility Rating
Other Uses Rating
Habit	Deciduous Tree
Height	8.00 m
Cultivation Status	Ornamental, Wild

Cultivation Details

Acer palmatum is a very cold-hardy plant, able to tolerate temperatures down to around -25°c, although the new growth in spring is subject to damage by late frosts[, , ].
Of easy cultivation, it succeeds in most soils preferring a good moist well-drained soil on the acid side and partial shade[, ]. Grows well in heavy clay soils. Chlorosis can sometimes develop as a result of iron deficiency when the plants are grown in alkaline soils, but in general maples are not fussy as to soil pH. Requires some shelter in the cooler areas of Britain and protection from cold drying winds[].
The best sap production comes from cold-winter areas with continental climates. The tree trunk is tapped in the early spring, the sap flowing better on warm sunny days following a frost.
A polymorphic species[], there are many named varieties[, ].
A very widely grown ornamental plant, especially in Japan. An extraordinary number and variety of forms have been developed, differing in colour and form of leaf[].
Grows well with rhododendrons.
Most maples are bad companion plants, inhibiting the growth of nearby plants[, ].

Edible Uses

The sap contains a certain amount of sugar and can either be used as a drink, or can be concentrated into a syrup by boiling off the water[, , ]. The syrup is used as a sweetener on many foods. The concentration of sugar is considerably lower than in the sugar maples (A. saccharum).

Leaves - cooked[, , ]. We have eaten nicer leaves[].

Medicinal

None known

Other Uses

We have two reports that the leaves of maple species, when laid in layers between crops such as apples, carrots and potatoes, have a preservative effect[, ]. The reports do not name any specific species[].

Propagation

Seed - best sown as soon as it is ripe in a cold frame, it usually germinates in the following spring. Pre-soak stored seed for 24 hours and then stratify for 2 - 4 months at 1 - 8°c. It can be slow to germinate. The seed can be harvested 'green' (when it has fully developed but before it has dried and produced any germination inhibitors) and sown immediately. It should germinate in late winter. If the seed is harvested too soon it will produce very weak plants or no plants at all[, ]. When large enough to handle, prick the seedlings out into individual pots and grow them on until they are 20cm or more tall before planting them out in their permanent positions.
Layering, which takes about 12 months, is successful with most species in this genus.
Cuttings of young shoots in early summer . The cuttings should have 2 - 3 pairs of leaves, plus one pair of buds at the base. Remove a very thin slice of bark at the base of the cutting, rooting is improved if a rooting hormone is used. The rooted cuttings must show new growth during the summer before being potted up otherwise they are unlikely to survive the winter. Only strong-growing cultivars succeed from cuttings, plants of the dissected or variegated cultivars will rarely grow into good plants.