Species

Allium cepaOnion

5 other cultivars

bulb corm tuber

Walla Walla Onion

Allium cepa 'Walla Walla'

The Story

Plant Bio

Allium cepa 'Walla Walla' is a long-day onion cultivar known for producing large, globe-shaped bulbs with a remarkably sweet and mild flavor, making them excellent for eating raw.

Developed in Walla Walla, Washington, this onion is prized for its low sulfur content, which contributes to its sweetness. It is typically grown as an annual.

Uses & Benefits:

Alliums add architectural height and striking spherical flower heads, enhancing garden verticality.

Their bulbs are edible with a mild onion flavor, useful in culinary dishes.

Attract pollinators like bees and butterflies, supporting local ecosystems.

SpeciesAllium cepaOnion

Essentials

At a Glance

Plant Type

Bulb Corm Tuber

Height

24 inches

Width

6 inches

Light

Full Sun

Zones

5, 6, 7, 8

Water

Moderate

Humidity

Average

Lifespan

Biennial, grown as an annual

Native To

Central Asia

Toxicity

Toxic to dogs and cats

Bloom period

Late spring – Early summer

In flower about 2 months of the year

Planting

How to Grow

Tuck bulbs 2-4 inches deep in well-drained soil in fall.
Water thoroughly after planting to settle soil.
Allow foliage to die back naturally for best bulb development.
Divide clumps every 3-4 years in late summer or early fall.
Mulch to conserve moisture and suppress weeds during winter.
Fertilize with a balanced, slow-release fertilizer in early spring.

Pro Tip

Plant bulbs in full sun with sandy, well-drained soil for optimal growth.

Keep It Thriving

Care Guide

Do

Water regularly during active growth 🌱
Apply mulch to retain moisture and regulate soil temperature
Fertilize in early spring to promote healthy flowering

Don't

Avoid overwatering to prevent bulb rot ❌
Do not plant in heavy clay soil without amendment
Avoid disturbing bulbs during dormancy

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Harvest
Pest Check
Plant

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Scented border with vertical interestWildflower meadow accentPerennial flower bed centerpiece

Companion Plants

Carrots Lettuce Tomatoes Rosemary Lavender

Multiply

Propagation Methods

Good to Know

Common Questions

Walla Walla Onion questions

What zones can Walla Walla Onion grow in?

Walla Walla Onion is hardy in USDA Zones 5–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Walla Walla Onion deer resistant?

Yes — Walla Walla Onion is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Walla Walla Onion bloom?

Walla Walla Onion typically blooms in late spring through early summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Walla Walla Onion need full sun?

Walla Walla Onion does best in full sun (6+ hours).