• 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

Mentha longifolia

horse mint

© Dorling Kindersley Ltd
  • Other common names horse mint
    brook mint

    water mint
    long-leaved mint

    see more
  • Synonyms Mentha sylvestris L.

  • Family Lamiaceae

  • Genus Mentha are aromatic, rhizomatous perennials with opposite, toothed leaves and small tubular flowers in spikes of whorls in summer

  • Details M. longifolia is a spreading perennial, to 1.2m, with hairy, green to grey-green leaves with a musty, minty smell. Branched, tapering spires of tiny, pale purple or white flowers are produced in mid- to late summer

  • Plant range Europe, N Africa, SW Asia

Characteristics

  • Foliage Deciduous

  • Habit Suckering

  • Fragrance Leaf

  • 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)

    H7

Colour

Sunlight

  • Full Sun

  • Partial Shade

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

  • Exposure Sheltered or Exposed

Soil

  • Chalk

    Chalk

  • Clay

    Clay

  • Sand

    Sand

  • Loam

    Loam

  • MoisturePoorly-drained, Moist but well-drained

  • SoilChalk, Clay, Sand, Loam

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 1-1.5 metres

  • Ultimate spread 1-1.5 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Grow in any moist soil, in any situation. To prevent spreading, restrict the root run

Propagation Propagate by seed or division in spring or autumn

Suggested planting locations and garden types Cottage & Informal Garden Wildlife Gardens

How to care

Pruning Cut back after flowering

Pests Can get caterpillars, cuckoo spit (froghoppers) and mint beetle

Diseases May be subject to powdery mildews and mint rust

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