Acer japonicum
Encyclopedia
Acer japonicum is a species of maple
native to Japan
, on Honshū
, Hokkaidō
, Kyūshū
(Nagasaki Prefecture
), and also southern Korea
.
It is a small deciduous
tree
growing to 5–10 m (rarely 15 m) tall, with a trunk
up to 40 cm diameter. The bark
is smooth on young trees, becoming rough and scaly on old trees. The shoots are slender, and thinly downy with whitish hairs. The leaves
are rounded, 7-15 cm diameter with 9–13 (rarely 7) serrate lobes incised to half or less of the diameter of the leaf; they are downy at first with white hairs, the hairs mostly lost by late summer except on the veins and the underside of the leaf; the petiole is 2–4 cm long and hairy. In autumn, the leaves turn bright orange to dark red. The flower
s are 1 cm diameter, dark purplish-red with five sepals and petals; they are produced 10–15 together in drooping corymbs in early spring as the leaves start to open. The fruit
is a paired samara
with the nutlets 7 mm diameter with a 20–25 mm wing, hanging under the leaves.
The closely related species Acer shirasawanum (Japanese, オオイタヤメイゲツ ooitayameigetsu) from southern Japan is sometimes included as a subspecies of A. japonicum. It is distinct in its hairless shoots, and usually smaller leaves. Another related species, Acer sieboldianum
(Japanese: コハウチワカエデ kohauchiwakaede), is best distinguished by its yellow (not red) flowers, and smooth bark even on old trees. It is more easily distinguished from Acer palmatum
, as that species rarely has leaves with more than seven lobes.
in temperate regions of Europe, North America, and elsewhere, though much less commonly than A. palmatum. In cultivation, it is often only a shrub
by tree with multiple trunks joining at ground-level..
Its preferred growing conditions are similar to those of A. palmatum, but it is sometimes considered more tolerant of cold, especially compared to the more delicate cultivars of the latter.
Numerous cultivar
s have been selected, some of which have their own common names (e.g. "Grape-leaf maple" for A. japonicum 'Vitifolium'). Other popular cultivars are 'Aconitifolium' which has deeply incised leaves, and 'Green Cascade', with drooping to pendulous branches. Because of their variation from the wild species, some cultivars are difficult to assign to species, and they have often been mis-labeled as cultivars of the other related species; notably 'Aureum' has commonly been cited as a cultivar of A. japonicum, but is actually derived from A. shirasawanum.
Cultivars of this maple are found in almost every maple collection including Esveld Aceretum
(Boskoop, Netherlands
) and the large Acer section of Arnold Arboretum (Boston, Massachusetts). They are also common in more general collections of horticulture
, such as Valley Gardens
(Surrey, England
).
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
native to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, on Honshū
Honshu
is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...
, Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
, Kyūshū
Kyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
(Nagasaki Prefecture
Nagasaki Prefecture
is a prefecture of Japan located on the island of Kyūshū. The capital is the city of Nagasaki.- History :Nagasaki Prefecture was created by merging of the western half of the former province of Hizen with the island provinces of Tsushima and Iki...
), and also southern Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
.
It is a small deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
growing to 5–10 m (rarely 15 m) tall, with a trunk
Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...
up to 40 cm diameter. The bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
is smooth on young trees, becoming rough and scaly on old trees. The shoots are slender, and thinly downy with whitish hairs. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are rounded, 7-15 cm diameter with 9–13 (rarely 7) serrate lobes incised to half or less of the diameter of the leaf; they are downy at first with white hairs, the hairs mostly lost by late summer except on the veins and the underside of the leaf; the petiole is 2–4 cm long and hairy. In autumn, the leaves turn bright orange to dark red. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are 1 cm diameter, dark purplish-red with five sepals and petals; they are produced 10–15 together in drooping corymbs in early spring as the leaves start to open. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a paired samara
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
with the nutlets 7 mm diameter with a 20–25 mm wing, hanging under the leaves.
The closely related species Acer shirasawanum (Japanese, オオイタヤメイゲツ ooitayameigetsu) from southern Japan is sometimes included as a subspecies of A. japonicum. It is distinct in its hairless shoots, and usually smaller leaves. Another related species, Acer sieboldianum
Acer sieboldianum
Acer sieboldianum is a species of maple native to Japan and common in the forests of Hokkaidō, Honshū, Shikoku and Kyūshū Islands; in the south of the range it is restricted to mountain forests...
(Japanese: コハウチワカエデ kohauchiwakaede), is best distinguished by its yellow (not red) flowers, and smooth bark even on old trees. It is more easily distinguished from Acer palmatum
Acer palmatum
Acer palmatum, called Japanese Maple or Smooth Japanese Maple is a species of woody plant native to Japan, North Korea, South Korea, China, eastern Mongolia, and southeast Russia. Many different cultivars of this maple have been selected and they are grown worldwide for their attractive leaf...
, as that species rarely has leaves with more than seven lobes.
Cultivation
A. japonicum is frequently cultivated as an ornamental plantOrnamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
in temperate regions of Europe, North America, and elsewhere, though much less commonly than A. palmatum. In cultivation, it is often only a shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
by tree with multiple trunks joining at ground-level..
Its preferred growing conditions are similar to those of A. palmatum, but it is sometimes considered more tolerant of cold, especially compared to the more delicate cultivars of the latter.
Numerous cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have been selected, some of which have their own common names (e.g. "Grape-leaf maple" for A. japonicum 'Vitifolium'). Other popular cultivars are 'Aconitifolium' which has deeply incised leaves, and 'Green Cascade', with drooping to pendulous branches. Because of their variation from the wild species, some cultivars are difficult to assign to species, and they have often been mis-labeled as cultivars of the other related species; notably 'Aureum' has commonly been cited as a cultivar of A. japonicum, but is actually derived from A. shirasawanum.
Cultivars of this maple are found in almost every maple collection including Esveld Aceretum
Esveld Aceretum
Esveld Aceretum is the largest collection of maples in the world. The aceretum is part of PlantenTuin Esveld, a family-owned commercial nursury in Boskoop, Netherlands that was founded in 1865. The term "aceretum" describes an arboretum devoted to maple trees and shrubs, i.e. plants belonging to...
(Boskoop, Netherlands
Boskoop
Boskoop is a town and municipality in the western Netherlands, in the province of South Holland. The municipality had a population of 15,217 in 2008, and covers an area of 16.96 km² of which 2.17 km² is water...
) and the large Acer section of Arnold Arboretum (Boston, Massachusetts). They are also common in more general collections of horticulture
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
, such as Valley Gardens
Valley Gardens
The Valley Gardens are of botanical garden, part of the Crown Estate located near Englefield Green in the English county of Surrey, on the eastern edge of Windsor Great Park.-Plants:...
(Surrey, England
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
).