Allium 'Cowanii' (neapolitanum)

50 bulbs
£4.89
£0.10 each
100 bulbs
£8.89
£0.09 each
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This variety is named in honor of William Douglas Cowan, a 19th-century plant collector who gathered specimens from southern Europe.

A vision of pure, bridal white, this allium brings delicate elegance and a fresh sparkle to the late spring garden. Often known as the Naples Garlic, 'Cowanii' is a select, more robust form that produces loose, airy umbels of pristine white, star-shaped flowers. Each floret features a subtle green eye, adding to its charm. Unlike the dense globes of other alliums, these blooms create a light, see-through effect, perfect for illuminating shady corners or weaving through bolder colours in a border. They are fantastic cut flowers, prized by florists for their long vase life and graceful appearance in bouquets. Plant them in generous sweeps to create a cloud of white that brightens the landscape and bridges the gap between spring bulbs and summer perennials.

Botanical name Allium neapolitanum 'Cowanii'
Flower colour Pure white
Bulb size 5/+ cm
Established height 30-40 cm
Established spread 5-10 cm
Plant spacing 150-200 bulbs per m²
Leaf colour Green
Habit Upright
Life cycle Perennial
Hardiness Hardy
Years to establish 1st year
Sunlight Full sun or partial shade
Position Sheltered
Suitable for Borders, Naturalizing
Soil acidity Any
Soil moisture Moist but well-drained
Soil type Loam, Sandy, Chalky
RHS Award (AGM) Yes
Growing skill Easy to grow
Pollinator-friendly Yes
Deer resistant Yes

Where to Plant:

This graceful allium, often called the Naples Garlic, thrives in a sunny, sheltered position. It performs best in fertile, well-drained soil and is an excellent choice for the front of a border, a rockery, or for growing in containers where its clusters of pure white, star-shaped flowers can be admired. It is also well-suited to a gravel garden. While it enjoys sun, it will also tolerate a small amount of light shade for part of the day, making it slightly more versatile than some of its relatives.

How to Plant:

Plant the bulbs in the autumn, from September to November. Position each bulb with the pointed tip facing upwards, at a depth of around 8-10cm. For a beautiful, full display that looks natural, plant them in generous drifts rather than dotted about singly. Space the bulbs approximately 8-10cm from one another to allow them room to form clumps. They are fantastic as a cut flower, so you may wish to plant a dedicated patch in a cutting garden. Water once after planting to settle them in.

Aftercare:

Once established, these plants are very low-maintenance. They will not require additional watering unless there is a prolonged period of drought during their spring growth. After the elegant flowers have faded, it is very important to allow the slender, grassy foliage to die back and yellow completely. This is how the bulb builds up energy for the following year's display. In suitable conditions, it may gently self-seed to increase your stock over time.

Planting and Flowering Calendar

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Key Features

Packed in paper

Packed peat-free

Great for Shade

Attracts wildlife

Fragrant

RHS Award (AGM)

Perfect for pots

Good for cutting

Naturalising

Allium 'Cowanii' (neapolitanum) - Harding & Bloom

Allium 'Cowanii' (neapolitanum)

£4.89

£4.89

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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