Boxes of fall bulbs ready for planting have begun to appear in the big box stores. As I’ve looked around here, I’ve seen a satisfying variety of daffodils, tulips, hyacinths and crocus available. Even some of the smaller, less familiar bulbs like Galanthus (Snowdrops) are well represented. Sticking just to these varieties, you could have the beginnings of a beautiful spring garden, but you’d most likely miss out on one of the most dramatic, and under-appreciated stars of the spring and summer garden, the allium.
Alliums are not only beautiful with their clustered blooms topping upright, leafless stems, they are remarkably hardy (many to -30 degrees F) almost maintenance free perennials. They are favorites of bees, butterflies and hummingbirds, but garden critters like deer, rabbits, voles and squirrels avoid them like the plague. In fact, many savvy gardeners strategically place allium bulbs throughout their borders to help keep more appetizing plants safe. Most alliums are excellent as fresh cut flowers but are also one of the easiest flowers to dry. Left standing in the garden, they add a unique, architectural dimension to the winter landscape.
With a wide range of bloom times, alliums can be the bridge between the delicate spring garden and the riotous summer garden. They are versatile plants pairing well with familiar perennials like hostas, astilbe and cranesbill geraniums. Large drifts of alliums intermingled with ornamental grasses in a prairie planting create a breathtaking display. Planted in the midst of cottage gardens, groupings of alliums give a feeling of strength and stability to an otherwise fluid design.
Like other spring flowering bulbs, alliums must be planted in the fall. The cooler fall temperatures and increased rainfall give the bulbs plenty of time to form root systems, while the colder winter months that follow allow flower buds to begin forming.
Alliums aren’t fussy about soil type, but they do insist on having good drainage. Sitting in consistently wet ground will rot bulbs. Alliums perform best in 6 or more hours of sun each day, but also appreciate some shade during the hottest parts of the day.
Plant allium bulbs three to four times deeper than the height of the bulb with the pointy side up. After planting, water well to make sure that the soil settles firmly around the bulb, eliminating air pockets. In extremely cold climates, mulch the newly planted bulbs with shredded leaves or compost. Then, sit back and wait for the spring show to begin.
For years, the most commonly seen allium bulb was the Globemaster with its 3 to 4 foot green stems and dark purple blooms. While it remains a popular choice for home gardeners, today there are literally hundreds of other varieties, including some native species, available in many garden centers and online. To make your garden planning easier, we’ve selected 14 outstanding allium varieties.
For the front of the garden, we suggest these alliums:
SCHUBERTII
- Referred to as “lavender fireworks”
- Stems up to 20 inches
- Up to 12 inch blooms
- Spiky purple blooms with green centers
- Very late spring
CHRISTOPHII
- Known as “Star of Persia”
- 16 inch stems
- Up to 10 inch blooms
- Silvery-lavender star-shaped blooms with green “eyes”
- Early to mid summer - June - July
MOLY
- Known as “golden garlic”
- 10 inch stem
- Yellow blooms
- Very late spring
For the middle of the garden, we suggest these alliums:
ATROPURPUREUM
- Heirloom variety
- 30 inch stems
- 2 inch blooms
- Dark burgundy blooms
- Late spring - May to June
PURPLE SENSATION
- 30 inch stems
- 4 inch blooms
- Violet-purple with shades of lavender and pink
- Late spring - May to June
MOUNT EVEREST
- 30 inch stems
- 5 to 7 inch blooms
- Snow white blooms
- Late spring May to June
CAERULEUM
- 24 inch stems
- 4 to 5 inch blooms
- Bright blue blooms
- Late spring - May to June
- Plant in groups of 10 to 15 bulbs
SPHAEROCEPHALON
- 24 inch stems
- Unusual drumstick shaped heads
- Dense green blooms maturing to maroon-purple
- Early spring - March to April
- Best in groups of 20 or more
For the back of the garden, we suggest these alliums:
AMBASSADOR
- 48 inch stems
- 7 inch blooms
- Light purple blooms
- Late spring - May to June
GIGANTEUM
- 48 inch stems
- 5 inch blooms
- Blooms begin green and change to bright lilac
- Early to mid summer - June to July
GLADIATOR
- 48 inch stems
- 6 inch blooms
- Blue-violet blooms
- Late spring - May to June
GLOBEMASTER
- 36 inch stems
- 8 to 10 inch blooms
- Purple blooms open slowly
- Late spring - May to June
Common Midwestern native alliums:
Stellaatum ( Prairie Onion)
- 12 to 18 inch stems
- Tiny, bell-shaped erect reddish-pink blooms
- Found on rocky prairies
- Mid to late summer - July to September
Cernuum (Nodding Onion)
- 12 to 18 inch stems
- Tiny, bell-shaped pink to lilac clusters of nodding blooms
- Found in rocky soils of glades and bluff edges
- Summer bloomer - June to August