Acer japonicum 'ACONITIFOLIUM' fullmoon maple, Japanese maple

Acer

Acer japonicum, the Japanese maple, is native to the mountainous regions of northern and central Honshu and to the island of Hokkaido, where it grows in cooler, humid forests as an understorey tree or multi‑stemmed shrub. It favours humus‑rich, well‑drained soils and a stable montane climate with high air humidity. It belongs to the same taxonomic group as Acer palmatum, A. shirasawanum and A. sieboldianum, but differs from A. palmatum in its more robust habit, larger and softer leaves, and the pronounced pubescence on young shoots and petioles. Compared with A. shirasawanum, its leaves are less symmetrical, with deeper sinuses and broader lobes, and its inflorescences are not upright but gently pendulous. The leaves usually have 9–11 broad, softly tipped lobes and turn vivid shades of red, orange and purple in autumn. The species was described in the 19th century by European botanists during a period of intense interest in the Japanese flora, and it soon entered collection gardens thanks to its robustness and striking autumn colour.

Acer japonicum is one of the traditional symbols of the Japanese autumn and stands alongside Acer palmatum in cultural awareness, even though in the wild it is more typical of the cooler regions of northern Japan. Its large, softly divided leaves with deep lobes are a prominent motif of momijigari (紅葉狩り) — the “hunt for red leaves”, when people travel to temple gardens, mountains and parks in search of the finest autumn colours. Compared with the finer palmatums, japonicum appears more robust, and its autumn palette — rich reds, oranges and purples — is perceived as a more dramatic, “northern” expression of Japanese autumn aesthetics. It appears in literature and art as early as the Man'yōshū, where maple leaves symbolise transience, beauty and the melancholy of the turning year. In painting, woodblock prints and textiles, japonicum is often depicted with emphasis on its broad lobes and intense autumn colours, which have become part of the visual identity of northern Japanese landscapes. The leaves are traditionally used in ikebana and seasonal decorations, appear in the tea ceremony as a motif of late autumn, and in some regions feature in culinary specialities associated with autumn festivals. Acer japonicum thus represents a distinct, northern and dramatically coloured branch of the Japanese maple tradition, deeply rooted in cultural memory and the aesthetics of the autumn season.

The modern era of Japanese maples is shaped by several key figures and institutions that define the direction of breeding and scholarly documentation. In the Western world, a pivotal role was played by the American dendrologist J. D. Vertrees (1920–1993), author of the first comprehensive monograph Japanese Maples, followed by the British specialist Peter Gregory, long‑time curator of the collection at Westonbirt Arboretum. In Europe, one of the most important centres is the Dutch arboretum and nursery Esveld, run by the van Gelderen family (est. 1865), while in Japan traditional nurseries such as Tsukasa Maple and Kobayashi Momiji‑en preserve old regional clones and introduce new cultivars. Among the world’s leading collections are Westonbirt Arboretum in the United Kingdom, the Arnold Arboretum of Harvard University (est. 1872), which has long studied the genus Acer, and the Portland Japanese Garden, where Japanese maples have become an iconic feature and the focus of expert care. In Japan, key institutions include the Kyoto Botanical Garden (est. 1924) and the Koishikawa Botanical Garden in Tokyo (est. 1684), both of which maintain the genetic diversity of native forms.