Purging buckthorn

Rhamnus cathartica

Spiny native shrub of chalk and limestone hedgerows. With alder buckthorn, an essential larval host for the brimstone butterfly.

Hardiness ratings

Purging buckthorn hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 3–7 −40 °C to −12.2 °C Plant tolerates down to this zone
RHS hardiness rating H7 down to −20 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 3–7 −34 °C to −7 °C Plant tolerates down to this zone
Australian (ANBG) zone Zone 2–5 −10 °C to 10 °C Plant tolerates down to this zone

Growing notes

  • Essential larval food plant for the brimstone butterfly, alongside alder buckthorn
  • Glossy black berries are eaten by birds and dispersed widely
  • Berries are strongly purgative — do not eat, the historic name reflects medicinal use that is no longer recommended

Categories

Related plants

Cross-check Purging buckthorn against your zones

Reference

Purging buckthorn on Wikipedia