Allium porrum 'Mammoth Pot'

RHS Plant Profile

leek 'Mammoth Pot Leek'

Synonyms

Allium porrum 'Mammoth Pot'

Herbaceous Perennial

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A large, hardy perennial usually grown as an annual vegetable, with thick, semi-upright, mid-green leaves and short, blanched stems. Bred for exhibition purposes due to the heavy leeks it produces, but has a good flavour and tight flesh, making it a great addition to stews, soups and other culinary uses. Sow from January to April for harvesting from September to January

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 1 year
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

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

Position

Full sun Partial shade

Aspect: South–facing or West–facing
Exposure: Exposed or 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): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Amaryllidaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Columnar upright
Genus: Allium are bulbous herbaceous perennials with a strong onion or garlic scent, linear, strap-shaped or cylindrical basal leaves and star-shaped or bell-shaped flowers in an umbel on a leafless stem
Name Status: Synonym

How to Grow

Cultivation

Grow in moist but well-drained soil that is rich in organic matter, preferably in full sun though they will tolerate partial shade. For longer blanched stems, draw up soil around the stems in late summer and early autumn. See leek cultivation for further advice

Propagation

Propagate by seed. See sowing vegetable seeds

Pruning

No pruning required

Pests

May be susceptible to slugs and snails, leek moth, onion fly, and onion Thrips

Diseases

May be susceptible to leek rust, although this variety shows some resistance, onion white rot, downy mildews, foot and root rots, fungal leaf spots, and smuts