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How to Grow Ornamental Allium

Reviewed by MyLocalPlanting Editorial Team Updated Sources
Ornamental Allium (Allium giganteum)

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🛠️ Supplies You'll Need

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🌿 Plant Overview

Scientific Name Allium giganteum
Category flower
Type Bulb (fall-planted)
Days to Maturity 210 days
Starting Method Plant Bulbs (Fall)

☀️ Growing Requirements

☀️

Sun

Full Sun (6+ hours)

💧

Water

Low to Moderate

↔️

Spacing

8" apart

🌱

Depth

6" deep

📏

Height

36-48"

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Companion Planting Guide for Ornamental Allium

Discover which plants grow well with Ornamental Allium and which to keep at a distance for a healthier garden →

🌾 Seed Saving Guide

🪴 Vegetative propagation

Propagate vegetatively, not by seed

Lift and separate bulb offsets in fall every few years; large bulbs may also be grown from seed but take 3+ years to bloom.

🪴

Raised Bed Planting Guides

A 4×8 bed fits 72 plants of Ornamental Allium. See plant counts, spacing grids, and companion pairings for every bed size →

Ornamental Allium Planting Calendar by Zone

Ornamental Allium Planting Calendar by State

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Frequently Asked Questions

When should I plant Ornamental Allium? +

Plant Ornamental Allium bulbs in fall, about 6 weeks before your area's first fall frost, so roots establish before the ground freezes. Use the search on this page to find exact dates for your location.

How long does Ornamental Allium take to grow? +

Ornamental Allium typically matures in about 210 days from planting. Exact timing varies by variety, soil conditions, and local climate.

Should I start Ornamental Allium indoors or direct sow? +

Ornamental Allium is planted as dormant bulbs directly in the garden — no indoor seed starting needed. Plant at the appropriate time based on your local frost dates.

How much sun does Ornamental Allium need? +

Ornamental Allium requires full sun (6+ hours) to thrive.

How far apart should I plant Ornamental Allium? +

Space Ornamental Allium plants 8 inches apart to allow adequate airflow and root development.

How much water does Ornamental Allium need? +

Ornamental Allium has low to moderate water needs. Consistent moisture is important especially during germination and early growth.

Can you save seeds from Ornamental Allium? +

Ornamental Allium is not typically propagated by seed. Lift and separate bulb offsets in fall every few years; large bulbs may also be grown from seed but take 3+ years to bloom.

About Ornamental Allium

Dramatic globe-shaped purple blooms on tall stems in late spring. Deer- and rodent-resistant like its onion relatives; plant in fall.

Expect your Ornamental Allium to be ready for harvest in approximately 210 days from planting.

Use the search above or browse by zone or state to find the perfect planting dates for your location.