• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

Acanthus spinosus L.

armed bear's breech

armed bear's breech

© � RHS 1990

  • Other common names armed bear's breech
    spiny bear's breech

    spiny bear's breeches

    see more
  • Synonyms Acanthus caroli-alexandri

  • Genus Acanthus are robust herbaceous perennials with handsome, lobed foliage and tall, erect racemes of two-lipped flowers with colourful bracts

  • Family Acanthaceae / Acanthaceae

  • Details A. spinosus is a handsome herbaceous perennial to 1.2m, with large, deeply lobed and spine-tipped, dark glossy green leaves. Erect spikes of white flowers with spiny purplish bracts in late spring and summer

  • Plant range Mediterranean


  • Foliage Deciduous

  • Habit Columnar/Upright



  • Full Sun

  • Partial Shade

  • Aspect South-facing or North-facing or East-facing or West-facing

  • Exposure Exposed or Sheltered


  • Chalk


  • Chalk


  • Chalk


  • MoistureWell-drained

  • SoilLoam, Chalk, Sand

  • pHAcid, Alkaline, Neutral


  • Ultimate height

    1-1.5 metres

  • Ultimate spread

    0.5-1 metres

  • Time to ultimate height

    2-5 years

How to grow

Cultivation The ideal soil is a deep, fertile, well-drained loam but it will grow in most soils and has good drought tolerance.

Propagation Propagate by division or by root cuttings

Suggested planting locations and garden types Drought Resistant Flower borders and beds Cut Flowers Low Maintenance Architectural Cottage & Informal Garden Mediterranean Climate Plants

How to care

Pruning Cut down old flower stems

Pests Generally pest free

Diseases Powdery mildews may be a problem

Advertise here

Did you find the information you were looking for?

RHS members can get exclusive individual advice from the RHS Gardening Advice team.

Join the RHS now