Allium porrum 'Mammoth Blanch'

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leek 'Mammoth Blanch'

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Herbaceous Perennial Herbs - Culinary
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A hardy perennial grown as an annual vegetable. This is a superior exhibition variety with an extra long white blanch and thick, broad flat. The root system will improve heavy soils

Position

Full sun

Soil Types

Sand, Loam, Clay, Chalk

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

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

Growing Conditions

Sand Loam Clay Chalk
Moisture
Well–drained
pH
Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–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)
H4

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Amaryllidaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Clump forming
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
Accepted

How to Grow

Cultivation

Grow in fertile, moist but well drained soil in full sun. Start in modules indoors between Jan-Feb and transplant out in early Summer, or sow outdoors between Mar-Apr and earth up the stems during the growing season to increase the length of the blanched stem. See leek cultivation

Propagation

Propagate by seed. See sowing vegetable seeds

Pruning

No pruning required

Pests

May be susceptible to onion fly

Diseases

May be susceptible to onion white rot, leek rust