The common name of Japanese maple is given to two different species - Acer japonicum and A. palmatum. A. japonicum grows slowly into a bushy tree with a single trunk or a shrub with multiple stems, reaching 5-10ft after ten years. A. palmatum is of similar stature, usually growing on one stem as a small tree, although its low and mounding growth gives it a shrubby appearance.

Both have beautiful foliage with typically lobed leaves. A. japonicum and its cultivars have 7-13 lobes per leaf, each growing to 3 - 5 1/2 inches long on downy stalks. A. palmatum has 5-7 lobes per 2 - 4in leaf, and there are so many variations that horticulturists have divided the species into three groups. There are cultivars with 5-lobed leaves, those with larger (up to 5in) 7-lobed leaves and those having finely divided thread-like 7-11 lobed leaves. It's the finely divided leaves that have led these to be named as the dissectum group. This is the group that includes those much-admired shrubs giving a sculpted effect due to their drooping branches.