• 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

Aponogeton distachyos

water hawthorn

  • Other common names water hawthorn
    water hyacinth

    Cape asparagus
    Cape pondweed
    hawthorn-scented pondweed
    winter hawthorn

    see more
  • Family Aponogetonaceae

  • Genus Aponogeton are submerged rhizomatous perennials with simple, floating leaves and small, white flowers in forked racemes or panicles held just above the surface

  • Details A. distachyos is a deciduous or partially evergreen perennial with elliptic or lance-shaped floating leaves and forked racemes of small, fragrant white flowers with purple anthers, held just above the water surface

  • Plant range S Africa


  • Foliage Deciduous

  • Habit Floating

  • Fragrance Flower

  • 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)




  • Partial Shade

  • Full Sun

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

  • Exposure Exposed or Sheltered


  • Sand


  • Clay


  • Loam


  • MoisturePoorly-drained

  • SoilSand, Clay, Loam

  • pHAcid, Alkaline, Neutral


  • Ultimate height Up to 10 cm

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 5-10 years

How to grow

Cultivation Grow in water 30-90cm deep in full sun or partial shade. This plant is listed on Schedule 3 of the EU (Birds and Natural Habitats) Regulations 2011 in the Republic of Ireland as an invasive non-native species. While this does not prevent it from being sold or from being grown in gardens in the Republic of Ireland, the RHS encourages those that do grow it to take great care with managing it and with disposing of unwanted material. The RHS also encourages gardeners in the Republic of Ireland to find alternative plants to grow to those listed on Schedule 3

Propagation Propagate by seed sown as soon as ripe or by rhizome division in spring

Suggested planting locations and garden types Sub-tropical

How to care

Pruning Cut back after flowering

Pests Water snail may cause damage

Diseases Generally disease free

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