Twigs tipped with thorns, leaves in opposite pairs with curved veins meeting at the tip, and black berries with a violent laxative effect
Purging buckthorn.
Nature · Shrubs
Purging buckthorn
Native · flowers May–Jun · chalk scrub and hedges, England and Wales
Rhamnus cathartica — Rhamnaceae
A small, spiny shrub of lime-rich scrub and hedgerows, named for the violent laxative effect of its berries. It is the chief food plant of the brimstone butterfly's caterpillars on chalky soils.
How to spot them
- ▸Opposite leaves with 3–5 pairs of curved veins that sweep towards the tip; glossy, dark green and toothed
- ▸Twigs that end in thorns, and orange bark under the peeled surface
- ▸Conical black-brown buds on long stalks
- ▸Purple-black berries 6–10 mm across on female plants (the sexes are on separate plants); flowers yellow-green with four petals
- ▸Look-alikes: alder buckthorn has alternate leaves and no thorns; dogwood is also opposite-leaved but has no thorns and smooth-edged leaves
How to know it
The main food plant for the caterpillars of the brimstone butterfly on chalky ground
Purging buckthorn.
Peel back the bark and the layer beneath is orange; its fruits and bark yielded a yellow dye
Purging buckthorn.
Which thorny shrub can be separated from a thornless relative by having opposite rather than alternate leaves?
Purging buckthorn versus alder buckthorn.
Male and female flowers occur on different plants on this dioecious shrub
Purging buckthorn.
Its species name cathartica refers to the purgative action that gave the shrub its common name
Purging buckthorn (Rhamnus cathartica).
Quick-fire facts
- •Rhamnus cathartica, family Rhamnaceae; cathartica means 'cleansing' — the berries are a strong laxative
- •Native to England and Wales and across Europe; grows to about 10 m (Woodland Trust)
- •Brimstone butterfly: purging buckthorn is the main food plant of the caterpillars on chalky soil; alder buckthorn on wet acid ground (Butterfly Conservation)
- •TOXICITY: the berries are slightly poisonous and can irritate the skin, as can the bark (Woodland Trust); do not eat them
- •Dioecious: separate male and female plants; seeds are spread by birds
- •Fruits and bark gave a traditional yellow dye
- •The brimstone butterfly, a hibernator, is one of the first to fly in spring and is thought to have given 'butterfly' its name via the male's butter-yellow wings
- •Woodland Trust warns against confusion with dogwood (not spiny) and alder buckthorn (alternate leaves)
Drill it — 6 cards
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Sources
- Woodland Trust — Purging buckthorn (Rhamnus cathartica)
- Butterfly Conservation — Brimstone