• 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

Tweedia coerulea

blue tweedia

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
blue tweedia

© RHS 2002

  • Other common names blue tweedia

  • Synonyms Oxypetalum caeruleum

  • Family Apocynaceae

  • Genus Tweedia is a scrambling evergreen subshrub with weakly twining stems bearing simple, hairy leaves and loose axillary clusters of star-shaped, 5-petalled flowers

  • Details T. coerulea is a scrambling or twining evergreen sub-shrub to 1m or more, with oblong to lance-shaped leaves and small clusters of 5-petalled, sky-blue flowers 2.5cm across

Characteristics

  • Foliage Evergreen

  • Habit Climbing

  • 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)

    H1C

Colour

Sunlight

  • Full Sun

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

  • Exposure Sheltered

Soil

  • Loam

    Loam

  • Chalk

    Chalk

  • Sand

    Sand

  • MoistureWell-drained, Moist but well-drained

  • SoilLoam, Chalk, Sand

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 0.5-1 metres

  • Ultimate spread 0.1-0.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Under glass grow in loam-based compost in full light; water freely in summer but keep just moist in winter. Can be grown outdoors in light, fertile, well-drained soil in frost-free area; can be treated as an annual in frost prone areas. Provide support for the climbing stems

Propagation Propagate by seed sown at 15°C in spring or strike softwood cuttings in summer with bottom heat

Suggested planting locations and garden types Wall-side Borders Cut Flowers City & Courtyard Gardens Patio & Container Plants

How to care

Pruning Pruning group 13 in early spring

Pests Generally pest free

Diseases Generally disease free

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