• 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

Myriophyllum spicatum

spiked water milfoil

spiked water milfoil

© RHS 2002

  • Other common names spiked water milfoil
    meakin

    water navelwort

    see more
  • Family Haloragaceae

  • Genus Myriophyllum can be submerged or marginal aquatic rhizomatous perennials, with finely dissected submerged leaves and small or minute flowers, solitary or in spikes from the leaf axils

  • Details M. spicatum is a submerged aquatic perennial with branched shoots bearing whorls of leaves pinnately divided into hairlike segments, with minute dull red flowers in spikes above the water surface, in summer

  • Plant range N.America, Europe, Asia, N.Africa

Characteristics

  • Foliage Deciduous

  • Habit Submerged

  • 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)

    H4

Colour

Sunlight

  • Full Sun

  • Aspect South-facing or West-facing

  • Exposure Sheltered or Exposed

Soil

  • Loam

    Loam

  • MoisturePoorly-drained

  • SoilLoam

  • pHAcid, Neutral, Alkaline

Size

  • Ultimate height Up to 10 cm

  • Ultimate spread 1-1.5 metres

  • Time to ultimate height 5-10 years

How to grow

Cultivation Grow in baskets of loamy soil in water at a depth of 1m in full sun

Propagation Propagate by cuttings of root segments

Suggested planting locations and garden types Low Maintenance Wildlife Gardens

How to care

Pruning Cut back regularly to avoid excessive growth

Pests Generally pest free

Diseases Generally disease free

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