Bulb

When to Plant Alliums (Ornamental)

Dramatic globe-shaped flower heads on tall stems, blooming in late spring. The ornamental cousins of onions and garlic.

Sun

Full sun (6+ hours)

Water

Moderate

Days to Harvest

180

Difficulty

beginner

Spacing

Frost Tolerance

high

The Short Answer

Alliums (Ornamental) are planted in fall, 8 weeks before your first frost date. They need winter cold to trigger their spring bloom. Enter your zip code on our homepage tool for exact dates.

How to Grow Alliums (Ornamental)

Ornamental alliums produce dramatic globe-shaped flower heads that look like something from a Dr. Seuss illustration. The 'Globemaster' variety produces softball-sized purple spheres on 3-foot stems. Plant bulbs in fall alongside tulips and daffodils — they bloom in the gap between spring bulbs and summer perennials. After flowering, the dried seed heads remain attractive for months and look spectacular in winter arrangements. Alliums are completely deer and rodent resistant (they're in the onion family, and critters avoid them). Interplant with perennials whose foliage hides the alliums' yellowing leaves.

Fall Planting

Alliums (Ornamental) are planted in fall, 8 weeks before your average first frost date. Plant 4" deep, 8" apart.

Growing Tips

Plant bulbs in fall alongside tulips and daffodils. Deer and rodent resistant. Dried seed heads remain attractive through winter. Giant alliums (Globemaster) produce softball-sized purple spheres.

Companion Planting

Good companions:

Roses Peonies Tomatoes

Alliums (Ornamental) Planting Dates by State

Click your state for alliums (ornamental) planting dates specific to your location:

Note: Planting dates are based on average frost dates from NOAA Climate Normals (30-year averages). Actual conditions vary year to year. Always check your local forecast before planting frost-sensitive crops.

Last reviewed: March 29, 2026