• 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

Strobilanthes dyeriana

royal purple plant

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
royal purple plant

© � RHS 2001

  • Other common names royal purple plant
    Persian shield

  • Synonyms Strobilanthes dyeriana 'Persian Shield'

  • Genus Strobilanthes can be evergreen or herbaceous perennials or subshrubs with simple, opposite leaves and spikes, cone-like clusters or loose panicles of tubular or funnel-shaped flowers

  • Family Acanthaceae / Acanthaceae

  • Details S. dyeriana is an evergreen shrub to 1m in height, the lance-shaped dark green leaves with a striking silvery sheen over a reddish-purple flush; flowers light blue, funnel-shaped, 3cm in length, in short terminal spikes

  • Plant range Myanmar

Characteristics

  • Foliage Evergreen

  • Habit Bushy

  • Hardiness

    Hardiness ratings

    All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

    • H1a - Under glass all year (>15C)
    • H1b - Can be grown outside in the summer (10 - 15)
    • H1c - Can be grown outside in the summer (5 - 10)
    • H2 - Tolerant of low temperatures, but not surviving being frozen (1 to 5)
    • H3 - Hardy in coastal and relatively mild parts of the UK (-5 to 1)
    • H4 - Hardy through most of the UK (-10 to -5)
    • H5 - Hardy in most places throughout the UK even in severe winters (-15 to -10)
    • H6 - Hardy in all of UK and northern Europe (-20 to -15)
    • H7 - Hardy in the severest European continental climates (< -20)
    Old hardiness ratings

    While we update our systems with the new hardiness ratings you may still see old hardiness ratings in your search results. These are denoted as 'Old'.

    • H1 - Requires heated glass
    • H2 - Requires unheated glass
    • H3 - Hardy outside in some regions of the UK
    • H4 - Hardy throughout the UK
    • H1 + H3 - Requires heated glass but may be grown outside in summer

    For full details of the hardiness ratings see

    see more

    H1b

Colour

Sunlight

  • Full Sun

  • Partial Shade

  • Aspect South-facing or East-facing

  • Exposure Sheltered

Soil

  • Chalk

    Sand

  • Chalk

    Loam

  • MoistureWell-drained

  • SoilSand, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height

    0.5-1 metres

  • Ultimate spread

    0.5-1 metres

  • Time to ultimate height

    5-10 years

How to grow

Cultivation Grow under glass in loam-based compost in full light with shade from hot sun. Grow outdoors in light free draining soil in full sun to partial shade in a frost-free area. Pinch out young growth to encourage bushiness

Propagation Propagate by seed or softwood cuttings

Suggested planting locations and garden types Low Maintenance Wall-side Borders

How to care

Pruning Pruning group 9

Pests May be attacked by glasshouse red spider mite

Diseases Generally disease free

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