Allium is the bulb that every designer garden seems to include, and once you discover why, you will wonder how you ever gardened without it. A member of the onion family, Allium produces perfectly spherical flower heads, sometimes as large as a softball, perched atop tall, elegant stems that rise like little beacons above the rest of the garden. She blooms from late spring to early summer in shades of purple, violet, white, and pink, filling the critical gap between the main flush of spring bulbs and the arrival of summer perennials. Allium thrives in zones 4–9 and is one of the most reliably deer- and rodent-resistant bulbs you can plant.
The Designer’s Secret for a Garden That Never Looks Empty
What makes Allium so valuable as a garden plant is not just her beauty when in bloom. It is what she does for the overall composition of the garden. Those tall, airy stems and perfect globe-shaped flower heads add a vertical punctuation mark and a structural quality that few other plants can match. Plant her among roses and watch the way those spheres of violet and purple echo and complement the softer, more complex forms of the blooms below. She is outstanding weaving through the mid-border alongside Salvia, Catmint, and just-opening roses for a late May display that looks effortlessly designed.
Allium is also clever about hiding her own flaw: the foliage, which can look a bit untidy as it yellows after bloom, is easily concealed by surrounding plants. Tuck her bulbs in behind low-growing perennials like Salvia or Geranium so that as the Allium foliage fades, the neighboring plants fill in and disguise it gracefully. The dried seed heads that remain after bloom are themselves a point of beauty, so leave them in place and enjoy the sculptural effect they bring to the garden through summer and into fall, when they can also provide interest in dried arrangements.
Pollinators absolutely love Allium. Bees and butterflies are attracted to her in enormous numbers when she is in bloom, making her an excellent addition to any pollinator-friendly garden. She is also completely deer resistant: the very characteristic that makes the onion family pungent to us makes it entirely unappealing to deer and other browsing animals.
Planting and Care
Watch our step-by-step planting tutorial below, then follow along with the written guide for all the details.
Plant Allium bulbs in fall alongside your Tulips and Daffodils. Choose a spot in full sun with well-draining soil, as Allium will not tolerate waterlogged conditions and is susceptible to rot in poorly draining sites. Dig holes 3–6 inches deep depending on the bulb size (a general rule is to plant at a depth four times the height of the bulb) and space bulbs 6–8 inches apart. Before placing each bulb, drop a teaspoon of Heirloom™ Bone Meal into the bottom of the hole and mix it into the soil. Then place the bulb, pointed end up, cover with soil, and water in well. No additional watering is needed until spring.
In spring as the foliage emerges, a light top-dressing of Founders Fish Fertilizer™ will support strong stem and bloom development; mix 4 oz into a gallon of water and apply around the base of the plants as growth picks up. Water during dry spells in spring when the plant is actively growing, but once the foliage has died back in summer, Allium is quite drought tolerant and will not need supplemental irrigation.
Allow the foliage to die back naturally, as the leaves are feeding the bulb and storing energy for next season’s flowers. Once the foliage is completely brown and dry, it can be pulled away cleanly. Many Allium varieties will naturalize and multiply over time, gradually building into larger and more impressive clumps with each passing year, making them one of the most rewarding bulbs in the long-term garden.
Three favorites for us this season are: Gladiator, a classic tall allium with large, perfectly round deep purple globes on sturdy stems; Purple Sensation, a deep, velvety purple with a rich intensity that photographs beautifully; and Drumstick Allium, a charming smaller variety with dark maroon buds that elongate into the most whimsical, sculptural drumstick shape.