Rhamnus japonica is a spreading, deciduous shrub growing up to 3 metres tall[
The plant is harvested from the wild for local use as a food, medicine and source of materials. It is grown as an ornamental.
Species in this genus contain hydroxyanthracene derivatives which have a stimulant laxative effect upon the body, and many species are used traditionally as laxatives. In small doses, and for short periods, these can be safe and effective, but used over long periods they can weaken the body's natural ability to defecate and can have a range of long-lasting negative effects upon the body, including anaemia, malabsorption, haematuria and weight loss. Large single doses can cause severe purging.
E. Asia - Japan (Hokkaido, Honshu, Kyushu, Shikoku).
Found all over Japan[
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Rhamnus japonica is a very cold-hardy plant, able to tolerate temperatures down to around -30°c when fully dormant[
Succeeds in any reasonably good soil[
A polymorphic species[
The species in this genus are notably resistant to honey fungus[
]. No more details but some caution is advised, see the notes above on toxicity.
The fruit and the bark are emetic and laxative[
]. They are recommended in the treatment of fevers, scrofulous sores, ascites, small-pox eruption, scabious sores etc[
The flowers are a good source of nectar for bees[
A green dye is obtained from the branches[
All the species of Rhamnus contain a mixture of compounds (mainly rhamnetin, quercitin and rhamnazin) that make a range of good quality dyes. The colour and its intensity depend upon what part of the plant is used as dyeing material (leaves, fruits and bark are most commonly used), at what period of growth it is collected and in what state it is used. With the use of the corresponding mordants (alum, copper and iron vitriols, tin dioxide, chromium, etc.) it is possible to obtain virtually the entire spectrum of colours from lemon-yellow to purple and dark cinnamon-brown, from olive-green to intensive blue and violet[
The dye extracts obtained from the bark, leaves and fruits are suitable for dyeing cottons, silks, woollens, leather, paper and wood. These dyes are often exceptional for their fastness[
Although we have seen no specific information for this species, the seeds of Rhamnus species are generally rich in fatty oil and several of them are extracted for use as lubricating oils etc[
The wood is close grained. It is used for making small furniture[
Seed - best sown in the autumn in a cold frame. Stored seed will require 1 - 2 months cold stratification at about 5° and should be sown as early in the year as possible in a cold frame or outdoor seedbed[
]. Prick out the seedlings into individual pots when they are large enough to handle, and grow them on in the greenhouse or cold frame for their first winter. Plant them out in late spring or early summer of the following year.
Cuttings of half-ripe wood, mid summer in a frame[
Cuttings of mature wood of the current year's growth, autumn in a frame.
Layering in early spring[