Rhamnus crocea and several closely related species were considered conspecific by C. B. Wolf (1938), who treated them as subspp. crocea, ilicifolia, insula, pilosa, and pirifolia. The taxa are distinctive, but intermediates exist[
]. We are following the treatment in the Flora of N. America and treating Rhamnus crocea in its strict sense as being native only in California. Rhamnus ilicifolia Kellogg, Rhamnus pilosa (Trelease ex Curran) Abrams,, Rhamnus insula Kellogg, and Rhamnus pirifolia Greene are not treated here, but it is likely that all the uses mentioned in this record will also apply to them[
Common Name: Spiny Redberry
Rhamnus crocea is an evergreen, spreading shrub, usually armed with thorns, growing 120 - 200 metres tall, occasionally to 400cm[
The plant is harvested from the wild for local use as a food and a medicine.
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.
South-western N. America - California to Arizona, south to Mexico.
Dry washes and canyons, coastal and inland dunes, alluvial fans, gravel flood plains, disturbed sandy flats, brushy slopes, steep granitic slopes, woodlands, coastal sage scrub, chaparral; at elevations from 50 - 1,200 metres[
Rhamnus crocea is not a very cold-hardy plant, able to tolerate short periods with temperatures down to around -8°c when fully dormant[
]. Another report says that plants are possibly hardy to -15°c if given hot summers to fully ripen their wood[
Succeeds in any reasonably good soil[
]. Requires a well-drained sunny site[
The sub-species R. croceus ilicifolia. Greene. often forms a tree up to 7 metres tall[
The species in this genus are notably resistant to honey fungus[
The flowers are produced in small clusters in the leaf axils or from small persistent bracts on shoots of the year[
]. Plants of this species can be hermaphrodite or dioecious[
]. If fruit and seed is required it is necessary to grow a hermaphrodite form, or male and female forms.
Fruit - raw[
]. A thin dry flesh[
]. If eaten in large quantities they can temporarily tinge the skin red[
]. The red, globose fruit is about 5 - 8mm in diameter and contains 2 seeds[
]. Some caution is advised, see the notes above on toxicity.
An extract of the bark is used as a mild laxative and tonic[
The flowers are a good source of nectar for bees[
We have no specific information for this species, but all the members of this genus 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[
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[
]. Germination is usually good, at least 80% by late spring. 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[