When Do Alliums Bloom?

Written by Hannah Miller and reviewed by horticulturist Elizabeth Smith. Published to Blog on the 9th June 2021.

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Hello, my name is Hannah Miller, and I’m the co-owner and contributor here at DIY Gardening.

Alliums have become so popular in recent years, it wasn’t long ago that I rarely saw them, but now I notice them in so many gardens.

While it’s impossible to predict when they will flower, the vast majority of Alliums will bloom from mid-May into June, with a few even continuing into July. Of course, this all depends on the general climate where you live and also whether spring comes early or late.

Below is my allium bloom time chart, which includes the most popular alliums.

(Click to expand the image and feel free to share)

Hannah Miller

Hannah Miller

Allium bloom time chart

My Favourite Alliums and When They Bloom

Purple Sensation Allium Bloom Time

If you’ve never grown alliums before, I recommend Purple Sensation as it’s an early bloomer, can be found in most garden centres in Autumn, grows to a height of 30″ (75cm) and produces a lovely pom-pom ball at its tip that isn’t too small but not too big either.

This year, my Purple Sensation alliums bloomed just as my tulip flowers started to wilt and drop off in May, so that gives you an idea of when they flower. They also lasted well over three weeks which is longer than I expected.

One of the great things about alliums is that you can leave them in place after they’ve finished flowering. By June, your other plants should have grown enough to hide the allium foliage, and you can leave the tall stem and old flower in the garden if you wish.

Some people cut the stem at the base and use the flower for floral arrangements indoors; I’ve even seen gardeners spray their old alliums with gold and silver paint as they look lovely at Christmas time.

(Update: Here are the cheapest places to buy allium bulbs in bulk)

Closeup of my allium Purple Sensation (2021)

Taken in my garden May 2021

Purple sensation blooming

This Purple Sensation bloomed in late May

Purple Sensation during the second week of June

By the second week of June, the flowers have started to fall off.

Allium Globemaster Bloom Time

The Globemaster produces the largest head of all the alliums, but it’s nowhere near the tallest at 25-35″ (65-90cm).

My Globemasters started to bloom during the first week of June in 2021, so well after the Purple Sensations, some of which started to fade just as the Globemaster got going.

Globemasters are like Marmite; some people love them as the heads are so huge (6-8″/15-20cm), and you can take some great photos of them, but others detest them as they do look a little odd in most gardens. Also, the ground-covering foliage produced by the Globemasters is huge, and it turns an unattractive yellow very quickly, so hiding it under more beautiful plants is a must.

My preference is the Purple Sensation, but if you’re thinking about growing alliums, give the Globemaster a try, it’s fun to watch the huge flower head slowing opening and then getting bigger and bigger until a near-perfect globe is formed.

Globemaster in early June

One of my Globemasters just starting to open up in the 1st week of June.

Allium Universe Bloom Time

This year, my Allium Universe plants bloomed at the same time as the Globemasters in late spring, but if I remember correctly, last year, they started flowering a little later in early summer.

A. Universe grow to 50cm (20″) and produce beautiful and unique slim, star-shaped flowers around a green node located in the centre.

The main difference between this allium and many others is the sparsity of the flowers in the head; there’s much more space for each of the “stars”.

Allium Universe is an unusual allium and very distinctive so give it a try.

Allium Universe
Allium Universe

Allium Sphaerocephalon (Drumstick Alliums) For Late Blooms

Allium sphaerocephalon is the perfect allium for those that want late bloomers in their gardens.

These drumstick alliums flower from late spring or early summer into mid-summer, and some even hang around for longer.

They have long, thin stems that can barely hold the weight of the drumstick head, which starts out green but, over the summer, transforms into maroon or purple.

I love these alliums as they flower at a time when my garden is in full growth, and the other plants hide the foliage of these alliums, leaving just a tall (18″/45cm) stem and beautiful drumstick swaying in the wind.

A.sphaerocephalaon is a great choice for those that want to see alliums persist into the summer. Give them a try; I’m sure you won’t be disappointed.

Drumstick alliums

When Do Alliums Flower? A Quick Recap

Allium bulbs are planted in the autumn and are grown as late spring and early summer flowers; they typically bloom after tulips in May and June, and some of the mid and late alliums will continue well into the summer.

Alliums are easy to grow (see How to Grow Alliums) and are resistant to most pests and diseases. They do require well-drained soil and prefer a sunny spot but are otherwise easy to grow. Some alliums have thin, tender stems, so should be planted in a location that shelters them from the wind.

You don’t need to lift alliums every year, but every 3-5 years, the bulbs could do with splitting. The success rate of alliums is very high, and unlike tulips, they come back year after year.

I love alliums, and they’ve become a mainstay in my garden. I prefer the Purple Sensations, but as with all alliums, one must choose the best companion plants to hide the unattractive foliage.

Want to Know the Best Time to Plant Alliums and Other Bulbs?

Our quick guide to the best time to plant alliums and other bulbs is a great read, go check it out.

Meet The Author: Hannah Miller

Hannah is a former NHS administrator, mother of two and keen gardener with a horticulture qualification who loves growing new plants and experimenting in the garden.

She enjoys gardening as much as she cares about the environment and likes to share her knowledge with others.

This year is all about pollinators, and Hannah has set herself the goal of only buying new plants that attract pollinators; she aims to make the garden as bee and butterfly friendly as possible.

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Hannah Miller has been growing alliums for over 7 years and created this guide for us.

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