Allium 'Sphaerocephalon' (Round-Headed Leek)

Dispatch begins week of 14 September
Autumn planting varieties are seasonal and become available at the start of September. We will then prepare your order and begin dispatch during the week beginning Monday 14 September.

Choose your pack size Planting impact; savings vs smallest pack
50 bulbs
Planting coverageCreates a broad border drift
£5.99
£0.12 each
100 bulbs
Most popular Plants a substantial border display
£9.89
£0.10 each
Save 17% each
250 bulbs
Best value Plants a large-scale display
£24.39
£0.10 each
Save 19% each

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Sphaerocephalon, often admired for its purple colouring, is a bulb variety especially well suited to borders.

Allium sphaerocephalon is a wonderfully refined choice for extending the season with poise. Slender stems rise above neat, narrow foliage, each topped with a dense, rounded head in rich pink to red tones—an elegant punctuation mark through early to late summer.

Superb threaded through borders or planted en masse for a light, rhythmic effect, it also suits generous pots where its upright habit brings height without heaviness. A quietly hardworking perennial, it is also valued for being pollinator friendly.

  • Bulb size: 8/10cm
  • Height: 50–100cm
  • Spread: 10–50cm
  • Flowering: June–August
  • Position: Full Sun, Partial Sun
  • Soil & moisture: Clay; well-drained
  • Hardiness: Fully Hardy
Botanical name Allium sphaerocephalon
Flower colour Purple
Bulb size 8/10cm
Established height 50–100cm
Established spread 10–50cm
Plant spacing 10–15cm
Leaf colour Green
Habit Clump-forming
Life cycle Perennial
Hardiness Fully Hardy
Years to establish 1
Sunlight Full-Sun, Partial Sun
Position Borders, Containers
Suitable for Borders, Containers, Cottage Gardens, City & Courtyard Gardens
Soil acidity Any
Soil moisture Well-drained
Soil type Clay
RHS Award (AGM) RHS Award of Garden Merit (AGM)
Growing skill Easy
Pollinator-friendly Yes
Deer resistant Yes

Where to Plant:

Allium 'Sphaerocephalon' (round-headed leek) needs full-sun, partial sun and a warm, sheltered position for the best flowering. Plant into fertile, humus-rich soil that drains well, and choose a spot protected from strong winds, especially for taller varieties.

How to Plant:

Plant bulb from September to December once conditions are suitable. Set them at the correct depth for the variety, spacing 10–15cm apart where relevant, then firm in gently and water well after planting.

Aftercare:

Water regularly in dry weather and feed every two to three weeks once buds appear. Stake taller stems early and deadhead to keep plants flowering. After flowering, allow foliage to die back naturally before lifting or protecting bulb according to local conditions.

Planting and Flowering Calendar

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Key Features

Packed in paper

Packed peat-free

Great for Shade

Attracts wildlife

RHS Award (AGM)

Good for cutting

Naturalising

Allium 'Sphaerocephalon' (round-headed leek) - Harding & Bloom

Allium 'Sphaerocephalon' (Round-Headed Leek)

£5.99

£5.99

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If a bulb or plant fails to perform in its first growing season after the care instructions have been followed, we will normally offer a replacement or store credit for the affected item. This does not affect your statutory rights.

Kind Words from Our Gardeners

Arrived quickly and well-packaged. Planted them in some pots on the patio and they all came up. Look beautiful. Thank you!

Careane Wallace

Oxfordshire, UK

The bulbs arrived beautifully packaged and you could just tell they were excellent quality. We had the most wonderful display of daffodils this spring on our patio. Simply stunning. Will definitely be ordering again

David P

Kent, UK

I ordered the mixed hyacinth collection and the scent in my garden this April was absolutely heavenly. Every single bulb produced a strong, beautiful flower and the colours were stunning together. A fantastic purchase, I'll be back for more next year!

Eleanor R

Somerset