1 named cultivar

‘Mount Everest’Mount Everest Onion

bulb corm tuber

Giant Onion

Allium gratisimum

The Story

Plant Bio

Tall perennial with impressive clusters of lilac-purple flowers.

Distinguished by its enormous, globe-shaped flower heads, up to 6 inches in diameter, on tall, leafless stems.

Uses & Benefits:

Allium gratisimum provides striking purple globe flowers that add architectural interest to gardens.

Its natural pest repellent properties help deter certain insect pests.

Supports pollinators like bees and butterflies during blooming season.

Essentials

At a Glance

Plant Type

Bulb Corm Tuber

Height

48 inches

Width

18 inches

Light

Full Sun

Zones

4, 5, 6, 7, 8

Water

Moderate

Humidity

Average

Lifespan

Perennial

Native To

Central Asia

Toxicity

Toxic to dogs and cats

Planting

How to Grow

Tuck bulbs 4 inches deep in well-draining soil in fall.
Water thoroughly after planting to settle soil.
Allow foliage to die back naturally for bulb health.
Divide clumps every 3-4 years in late summer.
Mulch lightly to retain moisture and control weeds.
Ensure full sun exposure for optimal growth.

Pro Tip

Plant in well-drained soil and avoid overwatering to prevent rot.

Keep It Thriving

Care Guide

Do

Water during dry periods 🌱
Apply balanced fertilizer in early spring
Allow foliage to yellow naturally before removal

Don't

Don’t overwater in winter ❌
Avoid planting in heavy clay soil
Don’t disturb bulbs during flowering

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Divide
Fertilize
Plant
Spring Cleanup

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Sparse ornamental bordersDry rock garden accentsWildflower meadow edges

Companion Plants

Sedum EchinaceaLavender CoreopsisYarrow

Multiply

Propagation Methods

Good to Know

Common Questions

Giant Onion questions

What zones can Giant Onion grow in?

Giant Onion is hardy in USDA Zones 4–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Giant Onion deer resistant?

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

When does Giant Onion bloom?

Giant 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 Giant Onion need full sun?

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

Is Giant Onion drought tolerant?

Yes — once established (usually after the first full season), Giant Onion handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.