Allium fistulosum 'Summer Isle'

RHS Plant Profile
onion (salad) 'Summer Isle'
Award of Garden MeritPlants for pollinators
Bulbs Herbs - Culinary

A bulb-forming perennial usually grown as an annual for its edible shoots. This late-maturing bunching or salad onion has a mild, sweet flavour and a good length of blanched stem. It can also have some ornamental value if left to flower, producing tightly clustered flower heads that are popular with bees

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0-0.1 metre

Size

Time to Maturity
1 year
Max Spread
0-0.1 metre
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
East–facing or South–facing or West–facing
Exposure
Exposed or Sheltered
Hardiness
H3

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Amaryllidaceae
Native to GB/Ireland
No
Foliage
Evergreen
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
Unresolved

How to Grow

Cultivation

Easy to grow in fertile, well-drained soil. See how to grow: salad onions for further advice

Propagation

Propagate by seed. See sowing vegetable seeds

Suggested planting locations and garden types

  • Wildlife gardens
  • Cottage and informal garden

Pruning

To harvest as a vegetable, lift the whole plant before flowering stems form. For ornamentals, remove faded flower heads to prevent self-seeding

Pests

May be susceptible to slugs and snails

Diseases

May be susceptible to onion white rot and downy mildew