25 Oct What Tree? Katsura
Katsura (Cercidiphyllum japonicum)
This non-native species is found in both Japan and China and was introduced to the UK in 1865. Katsura is the Japanese name for the tree and the genus name stems from the Greek word ‘Kerkis’ meaning Judas tree and ‘phyllon’ meaning a leaf. This tree is also referred to as the ‘candy floss/cotton’ tree and in Autumn the tree exudes a burnt sugar smell from foliage due to their high sugar content which smells like candy floss/toffee. It is also reported to smell like either freshly baked biscuits or bread, and links to the German name for the tree ‘Kuchenbaum’ which roughly translates to ‘cake tree’.
It is thought that this tree family (Cercidiphyllacae) may pre-date that of the Ginkgo, and is generally considered primitive due to having separate male and female trees (which is rare for hardwoods). In Japan, it is one of the largest growing hardwood trees, which can reach over 25m in height and live for over 1000 years, with its wood is not only used in the construction industry but also to make gobans (boards for the game GO).
Due to its relatively limited ultimate height, with rounded canopy and autumnal colour this is a popular species choice in gardens or landscapes. As you would expect, this species is also prevalent in a number of arboretums across the UK too.
Appearance and Identification
It is a deciduous tree, which is often multi-stemmed from its base with a dense rounded canopy that can reach to over 15m in height in the UK. Young trees often sucker from the base, which can lead to large-broad spreading canopies in maturity.
Mature Katsura at Arnold Arboretum (USA)
The leaves appear in pairs and are ovate to almost round, but often resembles a wide heart shape, with finely rounded-toothed edges. Young leaves have a deep bronze colour, which turn bluish green in summer. The underside of the leaf is also a blue-green colour. Autumn leaves range from yellow, burnt orange through to a striking red.
The leaves of the Katsura can resemble that of the Judas tree (Cercis siliquastrum), and link to the derivation of the genus name, but Judas leaves are easily identified as they are alternate, more rounded and untoothed.
Male trees produce tiny red flowers and female trees produce tiny green flowers and these appear in Spring before foliage. Pollinated flowers on female trees are followed by clusters of greenish pods.
In winter, the tree exhibits distinct thin red twigs and the trunk is smooth in early maturity, but becomes deeply grooved with peeling bark strips as the tree ages.
Propagation and Control
The tree has few known pests or diseases and is a relatively hardy species tolerating a range of climatic environments. However, the tree is shallow rooting and is susceptible to even minor disruption to the rooting environment and therefore thrives in deep, moist soil that is sheltered from the wind.
The leaves sprout early and therefore tree can suffer from frost damage but can usually responds well with limited long-lasting effects. In addition, due to their delicate nature, leaves may suffer scorch damage in particularly hot and dry periods.
Its overall resilience to UK climate has seen it become a stalwart of garden and landscape design.
Source and Reference Materials
Information detailed in this post has been obtained from the author’s own knowledge and photographic library where possible. Additional source of information and photographs include:
More, D & White, J. (2013). Illustrated trees of Britain and Europe. Domino.
Van den Berk, B.V. (2004). Van den Bek on Trees. Van den Berk Nurseries
Images