How to Combine Alliums with Perennials

How-to-Combine-Alliums-With-Perennials-Longfield-GardensGarden designers love using alliums and it’s easy to see why. These unusual and highly attractive flower globes grab your eyes with their bold shapes and sparkly florets. They bloom for weeks in late spring and early summer, and the seed heads add interest for months, long after the flowers are gone. Alliums are reliably perennial and not troubled by deer or rodents. Pollinators love them, too.

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Observing how garden designers combine alliums with perennials can be a great source of inspiration for your own garden. Read on to see some examples of creative and unexpected pairing. (Note: this article features alliums that are grown from fall-planted bulbs rather than herbaceous alliums such as Allium ‘Millenium’ and Allium tuberosum.)

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Allium Purple Sensation and Dictamnus albus (gas plant)

Combining Alliums with Other Perennials

Don’t make your alliums go it alone. With their long, slender stems, these flowers look better when there are other plants growing beneath them. Allium foliage also fades away shortly after the flowers bloom. If there are no other plants to fill in the gaps, you will be left with… gaps!

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Allium His Excellency planted among aquilegia, euphorbia and delphinium.

Here’s another good reason to have your alliums emerging from a bed of foliage. With some types, including Purple Sensation and most of the big-headed varieties, the leaves begin to yellow while the flowers are still in bloom. The best way to hide those leaves is with the foliage of other perennials.

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Allium christophii coming up through a bed of hosta.

Below is a list of perennials that work well with alliums. Later in the season many of them would be too tall. But the scale works because the perennials are still young when the alliums are in bloom.

  • Hosta
  • Upright Sedum
  • Ornamental grasses
  • Lady’s Mantle
  • Nepeta (catmint)
  • Salvia
  • Stachys (lamb’s ears)
  • Astilbe
  • Lavender
  • Geranium (cranesbill)
  • Aquilegia (columbine)
  • Dianthus (carnation)
  • Santolina
  • Peony
  • Hemerocallis (daylily)
  • Foxgloves

Here are some other combinations of alliums and perennials to inspire you:

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Allium atropurpureum rising from a bed of nepeta.

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Allium karataviense works works well in rock gardens. Sedums such as golden ‘Angelina’ are just the right scale to be good companions.

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In the garden of landscape designer Nick McCullough, allium Mt. Everest is underplanted with nepeta and salvia nemerosa.

How-to-Combine-Alliums-With-Perennials-Longfield-GardensPlan for Contrasting Heights

Some alliums will rise to a height of almost 4 feet, while others never get taller than 6 inches. This is why it’s important to know which types of allium you’re planting and where they are going.

Short ones like karataviense (6”), ‘Graceful’ (10”), christophii (18″) and schubertii (15”) can be planted near the front of a flower bed where they are easy to admire. Locate mid-size types in the middle and the tallest ones at the back. Or you can take a different approach and use tall alliums as “see through” plants — example below.

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Get Creative and Experiment with Color and Form

I saw the combination shown above at Trentham Gardens in Staffordshire, England. Waves of ornamental grass (Nassella tenuissima) were paired with big-headed alliums, possibly Gladiator. It was bold and surprising in the best sort of way and accentuated the distinctive forms of these two very different plants. Can you imagine a place in your garden where something like this might work?

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The seed heads of Purple Sensation are ideal companions for this eryngium.

Let the Seed Heads Linger

When alliums have finished blooming, don’t be too quick to remove the spent flowers. Let the show continue! Most types develop decorative seed heads that will persist for weeks or even months. This year it was early September before I finally pulled out the allium christophii and brought the seed heads indoors to enjoy around the house.

In the garden, allium seed heads look best when they str in a relatively open area that’s not too crowded with other plants. This makes it easier to appreciate their unique shape. Plus, good air circulation helps them stay dry and so they are less likely to fall apart.

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Planning for Different Bloom Times

Our Bloom Time Chart for Alliums shows when each type of allium blooms. This makes it easier to plan for specific plant pairings and also pace the bloom time so you can can have alliums flowering from May into early July.

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A favorite color harmony from this past spring: allium christophii with the burgundy-tipped leaves of a peony.

Alliums are available for shipping/planting from September-November, click HERE to see our selection. Learn more about growing alliums here: All About Alliums, Types of Alliums and Alliums for Every Garden. Garden designer Nick McCullough has also designed two allium-focused planting plans that are available free HERE and HERE.