Althaea cannabina

RHS Plant Profile

palm-leaf marsh mallow

RHS

Synonyms

Althaea narbonensis

Herbaceous Perennial

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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

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

1.5-2.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.5-1 metres
Max Height: 1.5-2.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: West–facing or East–facing or South–facing
Exposure: Sheltered
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 & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Malvaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Columnar upright
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
Name Status: Correct
Plant Range: Europe

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

Wildlife gardens
City and courtyard gardens
Cottage and informal garden
Mediterranean climate plants
Low Maintenance
Flower borders and beds
Wall side borders

Pruning

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

Pests

May be susceptible to flea beetles

Diseases

May be susceptible to hollyhock rust