'Purple Sensation' Allium Bulbs

• Variety: Purple Sensation
• Latin name: Allium hollandicum 'Purple Sensation'
• Type: A. hollandicum, a globe-headed ornamental onion (Dutch garlic)
• Colour: Deep rosy purple
• Height: 90cm (3ft)
• Flowering: May to June
• Naturalises: Yes. Clump forming, spreads by offsets and seed
• RHS AGM: Yes (1993)
• RHS Plants for Pollinators: Yes
• Sun/shade: Full sun
• Sold as: Premium size dry bulbs, in packs of 25
• Plant: In autumn, when the bulbs arrive, at 3 times their depth
• Delivered: September to December. Collection from Castle Cary also available

Purple Sensation is a globe-headed allium, 90cm (3ft) tall, with deep rosy-purple flowers in May and June. It holds the RHS Award of Garden Merit, and its leaves are mostly gone by the time the flowers open.

Purple Sensation Alliums: Purple Globes on a Metre of Bare Stem

Each globe is up to 8cm across and packs in 50 or more star-shaped flowers, held on a leafless stem that can reach a metre in a good year. Purple Sensation's grey-green leaves are already dying back as the flowers open, so plant something leafy in front to hide them.

Purple Sensation needs full sun and good drainage, and winter wet is the one thing it resents. Plant it in drifts of five or more, because a single globe looks like a lollipop that has wandered in from another garden.

Purple Sensation Allium History: A Dutch Selection From an Iranian Species

Despite the name, Allium hollandicum is a species from Iran (only a botanist could do that...). Purple Sensation is a deeper-coloured selection registered by the Dutch breeder Jan Bijl in 1963. You will still see it sold as Allium aflatunense 'Purple Sensation'; the RHS lists that name as a synonym, and the plant is the same.

Planting Partners for Purple Sensation

Plant it among shrub roses, where it grows up through the bare stems and flowers just before the roses open. Felicia, Fantin-Latour and Cardinal de Richelieu, from the rose collection, all flower in June.

The same border has room for two more Ashridge bulbs. Queen of Night, the maroon-black late tulip, flowers just before Purple Sensation, and the drumstick allium takes over once it has finished.

Why buy from Ashridge?

Ashridge Nurseries checks every bulb by hand and only sells premium sizes, because size is stored energy. Your bulbs are covered by our plant guarantee, and the rest of the alliums are in the ornamental onion collection. Feefo awarded Ashridge its Platinum Trusted Service Award.

Frequently Asked Questions

Do Purple Sensation alliums come back every year?

Yes, Purple Sensation is a perennial that flowers again each year and slowly forms a clump from offsets, as long as drainage is good. Winter wet is the usual reason a bulb fails to return.

How do I hide the dying leaves of Purple Sensation?

Plant something leafy in front, such as hardy geraniums, catmint or ornamental grasses, which grow up as the allium leaves fade. Don't cut them while they are green, because they feed the bulb.

Can I grow Purple Sensation in clay soil?

Only with help. Purple Sensation does best with good drainage and resents winter wet, so on clay add a bucket of grit to each planting hole and plant on a slight mound or in a raised bed.

Can I cut and dry Purple Sensation alliums?

Yes, cut stems last up to two weeks in a vase, and the seedheads dry well for winter arrangements. Change the water often, because the stems smell of onion.

What is the difference between Purple Sensation and Allium christophii?

Purple Sensation is taller, at 90cm against 60cm, with globes up to 8cm across in May and June. Allium christophii flowers in June, with silvery-violet heads up to 25cm across, and its seedheads last for months.

How deep should I plant Purple Sensation bulbs?

Plant each bulb at about 3 times its own depth, roughly 10cm (4in), pointed end up, and 10 to 15cm apart. You'll find the full method in the allium growing guide.