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Japanese Maple
Japanese Maple foliage
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Sapindales Family: Sapindaceae Genus: Acer Species: A. palmatum
Binomial name
Acer palmatum Thunb.

Japanese Maple (Acer palmatum) (Japanese: イロハカエデ, irohakaede) is a species of maple native to Japan, Korea, Taiwan and eastern China.

Contents 1 Characteristics 2 Cultivation and uses 2.1 Growing conditions 2.2 Cultivars 2.2.1 Example cultivars 2.3 Other varieties 2.4 Similar species 3 Gallery 4 References and external links

• A. palmatum is typically a tree reaching heights of about 15 m (50 feet) and often growing as an understory plant in shady woodlands. It may have multiple trunks joining close to the ground. In habit, it is often shaped like an upside-down pyramid (especially when younger) or takes on a dome-like form (especially when mature).^[1]
• Leaves of A. palmatum are about 5-12 cm long and wide, palmately lobed with approximately five to seven acutely pointed lobes.
• The flowers are produced in small cymes; the fruit is a pair of winged samaras, each samara 2-3 cm long with a 6-8 mm seed. The seeds of Japanese maple and similar species must be stratified in order to germinate.^[1].
• Even in nature, A. palmatum displays considerable genetic variation. As such, even seedlings with the same parent tree can show difference in such aspects as leaf size and shape, and color. ^[1].

• A. palmatum has been grown in temperate areas around the world since the 19th century and has been cultivated in Japan for centuries.^[1].
• Varieties of A. palmatum are readily available commercially and are a popular item at garden centres and other retail stores in Europe and North America. Red-leafed varieties of Japanese maple tree are the most popular, followed by cascading green shrubs with deeply dissected leaves.^[1]
• A. palmatum is also a popular and appropriate choice for bonsai enthusiasts and has been used in this art throughout its history.

• Like most maples, A. palmatum is somewhat adaptable but grows best in deep, well-drained, fertile soils.
• It grows well as an understory tree, tolerating fairly dense shade. However, they also cast deep shadows, making planting other plants under them difficult.
• Seedlings can become a nuisance, and the tree can become invasive in woodlands.

• Japanese Maple has over 1,000 cultivars that have been chosen for particular characteristics and can be propagated only by grafting. Some of these are not in cultivation in the Western world or have been lost over the generations, but new cultivars are developed each decade.^[1]
• These cultivars are chosen for such phenotypical aspects as leaf shape and size (shallowly to deeply lobed, some also palmately compound), leaf colour (ranging from chartreuse through dark green or from red to dark purple, others variegated with various patterns of white and pink), bark texture and colour, and growth pattern.
• Some cultivars of A. palmatum are sturdy trees that are larger and more hardy or vigorous than the species. Many are shrubs rarely reaching over 0.5 m in height. A few very delicate cultivars are typically grown in pots and rarely reaching heights of more than 50-100 cm.
• Some of the more distorted or dwarfed cultivars of A. palmatum are grown from witch's brooms, but more are based upon based upon clippings taken from plants that are mutated and/or have been artificially selected over many generations.^[1].
• Many cultivars have characteristics that come into prominence during different seasons, including the color of new or mature leaves, extraordinary fall color, color and shape of samaras, or even bark that becomes more brightly-colored during the winter.
• Some cultivars can scarcely be distinguished from others unless labeled. In some cases, identical cultivars go by different name. Conversely, different cultivars go by the same name in other cases.

A small list of notable or popular cultivars (with brief notes about characteristics that apply during at least one season) includes the following.^[1]

• 'Aka shigitatsu sawa', pinkish-white leaves with green veins
• 'Ao ba jo' - a dwarf with bronze-green summer foliage
• 'Atropurpureum' - wine-red in color, including new branches
• 'Bloodgood' - an improved variety of 'Atropurpureum'
• 'Butterfly' - small leaves with white borders
• 'Dissectum' - lace-like leaves, drooping habit
• 'Golden Pond' - greenish-yellow summer color
• 'Goshiki koto hime' - a delicate, variegated dwarf
• 'Higasa yama' - crinkled leaves variegated with yellow
• 'Hupp's Dwarf' - a small, dense shrub with miniature leaves
• 'Issai nishiki kawazu' - very rough, rigid bark
• 'Kagiri nishiki' - similar to 'Butterfly' but more pinkish tones
• 'Karasu gawa' - slow-growing variegate with brilliant pink and white
• 'Katsura' -yellow-green leaves tipped with orange
• 'Koto no ito' - thread-like leaves with light green color
• 'Little Princess' - a sparsely-branched dwarf with irregular habit
• 'Mama'- a bushy dwarf with extremely variable foliage
• 'Masu murasaki' - a shrubby tree with purple leaves
• 'Mizu kuguri' - orange-tinted new growth and very wide habit
• 'Nishiki gawa' - pinetree-like park desirable for bonsai
• 'Nomura nishiki' - dark purple, lace-like leaves
• 'Ojishi' - tiny dwarf, grows only centimeters per year
• 'Osakazuki' - tree-like shrub with spectacular autumn color
• 'Peaches and Cream' - similar to 'Aka shigitatsu sawa'
• 'Pink Filigree' - finely dissected, brownish-pink leaves
• 'Red Filigree Lace' - delicate, finely dissected, dark purple
• 'Sango kaku' - "coralbark maple" with pinkish-red wood
• 'Seiryu' - a green, tree-like shrub with finely dissected leaves
• 'Shikage ori nishiki'- vase-shaped shrub with dull purple foliage
• 'Skeeter's Broom' - derived from a 'Bloodgood' witches' broom
• 'Tamukeyama' - finely dissected, dark purple, cascading habit
• 'Tropenburg' - slender, upright grower, convex lobes, purple color
• 'Tsuma gaki' - yellow leaves with reddish-purple borders
• 'Uki gumo' - prominent white-speckled variegation
• 'Waka momiji' - another "coralbark" maple
• 'Yuba e' - upright tree with scarlet variegation

• In addition to the myriad cultivars described above, there are also a number of varieties of A. palmatum that have been naturally selected over time to such an extent that seedlings usually resemble the parent.
• Many of these are sold under the same name as the cultivars, or even propagated by grafting, so there is often much ambiguity in distinguishing them.^[1].
• In particular, a number of dark-red Japanese maples are sold with the names "Atropurpureum" and "Bloodgood". Many maples with delicate lace-like foliage are sold under names such as "Dissectum", "Filigree" and "Laceleaf."^[1].
• Fortunately, as long as a sapling looks healthy and has leaves and habit characteristic of what the buyer wants, the "authenticity" of a given variety or cultivar should not be a great concern in most cases.

The term "Japanese Maple" is sometimes used to describe other species within series Palmata that are similar to A. Palmatum and are native to Japan and/or Korea including:

• A. japonicum - Downy Japanese Maple
• A. pseudosieboldianum - Korean Maple
• A. shirasawanum - Fullmoon Maple
• A. sieboldianum - Siebold's Maple

Given that these maples are phenotypically variable within each species, and may hybridize with one another, distinguishing between them may be a matter of gradient speciation. In commercial propagation, A. palmatum is often used as rootstock for these other Palmata.^[1]

Momiji (A. palmatum) shows autumn colours in Kyoto, Japan.	A bronze-red cultivar of A. palmatum	A green "dissectum"-type A. palmatum	A red "dissectum"-type A. palmatum
trunk of A. palmatum 'Osakazuki'	Foliage of A. palmatum 'Osakazuki'	Wide view of A. palmatum 'Osakazuki	New leaves on A. palmatum 'Sango kaku', a "coralbark maple"
A. palmatum 'Sango kaku', a "coralbark maple" in winter showing red bark	A. palmatum samaras and leaves	A. palmatum 'Shigitatsu sawa'	Red variety of A. palmatum used for bonsai

• Plants for a Future: Acer palmatum
• Japanese Maple Photo Album
• RHS: Acer palmatum cultivation
• Collection of maples (Acer palmatum) by Guy Maillot

1. ^ ^{a b c d e f g h i j k} van Gelderen, C.J. & van Gelderen, D.M. (1999). Maples for Gardens: A Color Encyclopedia.

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