• 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

Althaea cannabina

palm-leaf marsh mallow

  • Other common names palm-leaf marsh mallow

  • Synonyms Althaea narbonensis

  • Family Malvaceae

  • Genus Althaea are annuals or perennials with strong, wiry stems and broadly oval, lobed leaves. Sprays of small, pink to bluish-purple, five-petalled flowers are produced from summer to autumn

  • Details A. cannabina is an erect, woody-based herbaceous perennial with strong stems, up to 2m high, hairy, lobed leaves, up to 35cm long, and cup-shaped flowers, 3-5cm across. Flowers appear singly or in clusters on long stalks from the leaf axils and are lavender-pink with dark pink-purple anthers, from midsummer to early autumn

  • Plant range Europe

Characteristics

  • Foliage Deciduous

  • Habit Columnar/Upright

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

  • Exposure Sheltered

Soil

  • Sand

    Sand

  • Clay

    Clay

  • Loam

    Loam

  • Chalk

    Chalk

  • MoistureWell-drained, Moist but well-drained

  • SoilSand, Clay, Loam, Chalk

  • pHAcid, Alkaline, Neutral

Size

  • Ultimate height 1.5-2.5 metres

  • Ultimate spread 0.5-1 metres

  • Time to ultimate height 2-5 years

How to grow

Cultivation Will tolerate a wide range of situations, and rarely needs staking; for best results grow in fertile, moist but well-drained soil in full sun

Propagation Propagate by seed or by division

Suggested planting locations and garden types Flower borders and beds Wall-side Borders Low Maintenance Wildlife Gardens City & Courtyard Gardens Cottage & Informal Garden Mediterranean Climate Plants

How to care

Pruning No pruning required, but stems can be cut to the ground once flowering is over

Pests May be affected by flea beetles

Diseases May be affected by hollyhock rust

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