How to Grow Alliums

 Alliums are an easy to grow bulb which is perennial and usually returns reliably every year.   

Alliums come in a wide range of heights, from low growing chives to the tall varieties such as A. allium giganteum which can reach 1.5m. Alliums are mainly late spring/early summer flowering, although there is a late summer flowering variety Allium sphaerocephalon .

Alliums flower in shades of purple, white and occasionally blue and yellow. Alliums are bulbs and almost trouble free. The only maintenance required is that the taller species need staking to prevent the flower stem from being damaged, unless planted in a sheltered spot away from wind. Bees and insects love alliums, and on a warm day the large flower heads will be buzzing and they will also attract butterflies.

Allium showing base leaves

The downside of growing Alliums, if there is one, is that the leaves at the base of the plant can look tired, or ragged early in the growing season. If you look closely at the image on the left, you will see the brown tips on the Allium leaves, which can look unsightly.  To cover this, it's a good idea to conceal the base growth with low-growing plants, such as the Alchemilla mollis, Hosta and Geraniums, all of which look well with Alliums. There are several planting combinations illustrated below which will look stylish and ensure the base leaves are covered. 

How To Plant Alliums

Allium Bulbs are best planted in the autumn when you can buy bulbs much cheaper than in the Spring when they are sold as pot grown plants. Planting time is September, but if you are late, you can carry on planting Allium bulbs until about the 3rd week of October.

Ready grown container plants are available from early spring onward, but naturally these are more expensive. It is significantly cheaper to buy and plant Alliums as bulbs. Alliums prefer a sunny position in soil which is well drained and they are drought tolerant. Alliums are fully hardy tolerating our winters well. However, if your garden has heavy soil or ground that is wet, it will help to work horticultural grit into the planting area to increase drainage. This should prevent the bulb rotting over winter, which can be a problem in wetter areas.

When planting Alliums, in common with many bulbs, plant to 3 times the depth of the bulb and plant the pointed end upward.

Smaller varieties should be planted 15-20 cms apart, large varieties (such as a.cristophii)  25-30cms and the very large ( such as Globemaster' and schubertii)35cms+ 

Like all bulbs, do not cut or clear away the old foliage after flowering,  this is needed to photosynthesise and feed the bulb for next year.

Alliums are drought tolerant, generally do not need feeding or dead heading, quite the reverse as many of the flower heads look decorative as they fade. 

Green wheelbarrow means Alliums are easy to grow and low maintenance

The Best Alliums to Grow

 

Individual plants make an impressive single statement in the border, (top left) and the Allium illustrated is 'Globemaster'. Alliums are predominately purple flowering although there is a blue form, careruleum, and a very attractive yellow variety, Allium moly (golden garlic) which has umbel type flowers in the summer. Alliums have an additional bonus that the flower heads look good as they fade and as the seed heads form, illustrated below right.

Alliums are members of the onion family and the small Allium schoenoprasum, Chives, are good to eat and make a lovely edging plant in the front of a border and are wildlife friendly. 

 Allium illustrated above are -

A. cristophii (image top right) is short at 60cms with spiky flower head, which will self seed in the right conditions;

A.hollandicum (image below) 'Purple Sensation' tall 80cms dark purple;

A. Globemaster 100cmc with large deep purple flower heads.

Centre image above is Allium sphaerocephalon, a late summer flowering variety. It looks good planted with grasses which are at their best in late summer and early autumn, and also with late flowering perennials such as Rudbeckia and Helenium.

In the third image above is the very attractive A. christophii which flowers in the late spring and early summer, with spiky flower heads which look very good as they fade and dry.

Chives are one of the smallest forms of Allium and a bee and butterfly magnet. The brief video clip shows pollinators on Allium nutans, also known as Siberian Chives, which are a great favourite. Often plants are described as "good for pollinators," here is the material evidence which should give you confidence when planting them. 

Alliums in the Border

Alliums in Border close up

This is the same border in both images taken from a different position. On the left, a closeup of Alliums grouped together, looking stunning. 

On the right, showing how the Alliums have been repeat planted along the border to great effect. I took the left image from the bench which is in the corner of the right image. All taken at Beningbrough Hall, a good garden for a visit.

Alliums in border long shot

Varieties of Allium

Allium christophii

Allium christophii

Allium Globemaster

Allium Globemaster

Allium sphaerocephalon

Allium sphaerocephalon

Allium 'White Giant'

Allium white giant

Allium 'Pinball Wizard'

Allium 'Pinball Wizard'

Allium schubertii

Allium schubertii - Schubert`s allium

Blue Allium caeruleum

Allium nectaroscordum

allium nectaroscordum siculum

Best Allium Planting Combinations

Allium hollandicum ‘purple sensation’ with Euphorbia palustris

For contrasting colours: Allium 'Purple Sensation' with Euphorbia palustris which make a great contrasting combination. This is a late spring early summer combination.

Allium stipitatum ‘white giant”

Simplicity: Allium stipitatum White Giant which looks really good planted as a group with the wall as a backdrop.

Alliums planted en masse

For a Soft Blues and Mauve combination: Alliums grouped together look impressive. This and the larger image (below) was taken at RHS Harlow Carr. In this image Alliums are planted with a blue variety of Camassia. This is a good blue/purple combination bearing in mind Camassia may not be fully hardy everywhere in the UK.

Deschampia grasses with Alliums

Late summer combination: Alliums and grasses are natural companions; this combination is Deschampsia grass with Allium sphaerocephalon, a soft billowing grass making a rich late summer/autumn display combined with the deep purple Allium and just a little blue mixed in from the Nigella damascena common name "love-in-a-mist'.

Allium chives, in wildflower setting with campion and for get me nots

Wildlife friendly combination: Chives with forget me nots and Campion. It is easy to overlook A. schoenoprasum, Chives, is small but ideal for edging and at the front of a border and it is very bee friendly. Chives flower for weeks and can be cut back to produce fresh growth and a second set of flowers.

Fading flower heads of Alliums

Staying Power: Allium fading flower head last for a long time looking impressive. This image shows the delicate beauty of the fading flower heads. Alliums belong to a unique group of plants whose flowers look really good as they fade, (think also Hydrangea, and Achillea.)

Allium schubertii, with candelabra primular and blue geranium 310

Great spring combination: The architectural spikey Allium schubertii, with candelabra primula and a hardy blue geranium, makes an easy to grow colourful combination

Allium against a backdrop of clematis montana

A soft colour combination of Allium Globemaster against a back drop of the spring flowering Clematis montana makes an interesting combination.

The RHS always knows how to put on an impressive display and this is Alliums on mass with grasses growing at RHS Harlow Carr, something to aspire to. 

Allium and grasses at RHS Harlow Carr

Updated 09.10.2021