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Tree Species: Purging buckthorn (Rhamnus cathartica)

Oliver Lewis avatar
Written by Oliver Lewis
Updated yesterday

1. Native / Non-native Status

Native to the UK, Europe, and parts of Asia.

2. Evergreen / Deciduous

Deciduous – leaves fall in autumn.

3. Appearance

Leaves: Small (2–6 cm), oval to elliptic with finely toothed margins. Dark glossy green, with opposite or nearly opposite arrangement (unusual for shrubs/trees).

Bark: Grey-brown, smooth when young, becoming fissured with age. Twigs often end in sharp spines.

Flowers/Fruit/Seeds: Small greenish-yellow flowers in late spring, borne in clusters. Female plants produce black berries (about 6–10 mm), ripening in late summer. Fruits contain 2–4 seeds.

Overall shape: Typically a shrub or small tree, often multi-stemmed, with a bushy, rounded crown and thorny twigs.

4. Typical Size

3–6 m tall; spread 3–5 m.

5. Habitat & Range

Widespread in the UK, especially in scrub, hedgerows, woodland edges, and chalk or limestone soils. Tolerant of dry, calcareous conditions.

6. Distinctive Features (ID tips)

Opposite (or nearly opposite) glossy leaves with fine teeth.

Twigs tipped with sharp spines.

Black berries on female plants.

7. Seasonal Changes

Spring: Small greenish flowers appear.

Summer: Dense green foliage; fruits forming on female plants.

Autumn: Leaves turn yellow; berries ripen black.

Winter: Bare, with thorny twigs prominent.

8. Human Uses

Berries were historically used as a strong laxative (hence “purging”), though toxic in larger amounts.

Bark and fruit used for dyes (yellow and green).

Sometimes used in traditional hedging.

9. Wildlife Value

Flowers provide nectar and pollen for bees and insects.

Fruits eaten by birds such as thrushes, which spread the seeds.

Important larval foodplant of the Brimstone butterfly (Gonepteryx rhamni).

10. Fun Fact / Cultural Note

Its name “cathartica” reflects its use as a purgative in traditional medicine.

Considered a “shrub of the chalk downs,” often associated with ancient hedgerows and scrub.

11. Planting & Care (Basic Instructions)

Best time to plant: Late autumn or early spring.

Soil: Prefers well-drained, chalky or limestone soils; tolerates sandy and clay loams.

Light: Full sun to partial shade.

Watering: Water regularly until established; tolerates drought once mature.

Spacing: 2–3 m apart for naturalistic planting; 30–60 cm for hedges.

Aftercare: Mulch to conserve moisture. Prune in winter if needed to shape. Protect young plants from browsing animals.

12. Good for Urban or Garden Setting?

Urban: Rarely planted due to thorns and toxic berries, though useful in wildlife corridors.

Garden: Suitable for larger wildlife gardens, especially on chalk soils, but not ideal for small family gardens because of spines and purgative berries.

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