2027 is the Year of the Allium: Planting, Care, and Garden Ideas

Purchasing Alliums

Alliums, like other spring-flowering bulbs, must be purchased and planted in the fall as bulbs. They need to spend winter in the ground. Their foliage emerges in early spring, followed by their flowers, which appear much later. So you have to plan ahead with these plants. You may find potted bulbs at the garden center in the spring. They will cost two or three times the price of a bulb purchased in the fall. (Note: Summer-flowering alliums grow like a perennial and are always sold in containers.)

Determining Whether Alliums are Suited to Your Climate

Alliums are generally cold hardy to USDA Zone 4a, which makes them suitable for most of the United States. In the South, they are typically suitable up to Zone 7b, but they do not perform well in extreme humidity or heavy clay soil. Because they prefer heat and dry summer conditions, they generally grow well in Southern California. In the desert Southwest, they may need supplemental irrigation, as most garden plants do. State agricultural regulations prohibit shipment of allium bulbs to Idaho and Oregon and to Adams, Benton, Franklin, Grant, and Klickitat counties in Washington state.

Choosing a Location for Alliums

Alliums require full sun, at least 6 hours of direct sunlight each day, to produce the strongest stems and largest flowers. Alliums grow best in average, dry to moderately moist, well-drained soil. They prefer full sun but can tolerate partial shade and light afternoon shade in hot-summer regions. They adapt to many soil types and thrive in sandy soils. In heavier clay soils, add compost or other organic matter to improve drainage and support healthy growth.

How Deep to Plant Allium Bulbs

Large allium bulbs are generally planted individually.

• Dig a hole to a depth equal to about three times the diameter of the bulb.
• Set the bulb in the hole with the point facing up.
• Cover with soil and repeat.

Small alliums can be planted singly, as above, or in large groups.

• When planting in groups, remove soil to the appropriate depth and place the soil in a large bucket or on a piece of cardboard.
• Set the bulbs points up in the excavated area.
• Replace the soil.

If the soil is dry and no rain is expected, water thoroughly after planting.

Caring for Alliums 

Alliums do not require much special care. They need consistent moisture from fall, when they form roots, until they finish flowering in spring. In the eastern half of the United States, rain or snow usually provides enough moisture. After bloom, stop supplemental irrigation if possible; the bulbs prefer dry summer conditions.

Alliums generally get by just fine on whatever nutrients are present in your soil. Fertilizer is rarely required.  Avoid excessive nitrogen, which encourages foliage at the expense of flowers.

How to Care for Allium Bulbs after Flowering

Like all spring-flowering bulbs, alliums go dormant after they bloom. If they leave a hole, consider planting summer annuals at their feet.

Using Alliums in the Garden

The big alliums can be massed, but they are often more effective when they are sprinkled—one by one or in small clusters—through the center of a bed or border. Sprinkling lets visitors appreciate the size and shape of the flower heads and helps tie a garden together.

Small alliums are best used in groups near a path or at the edge of a bed. A single bulb of a small allium like Moly will have little impact. Plant small bulbs close together and in quantity.

Companion Plants to Use with Alliums

Since allium foliage begins fading while flowers are still blooming, plant companions nearby to disguise yellowing leaves.

Excellent companions include:

• Hostas
• Ferns
• Catmint
• Hardy geraniums
• Salvia
• Peonies
• Lady’s mantle
• Ornamental grasses

The tall, narrow flower stalks also weave beautifully through perennial borders without taking up much space.