Photo by Melody

PlantFiles: Black Garlic, Flowering Onion
Allium nigrum

Family: Alliaceae
Genus: Allium (AL-ee-um) (Info)
Species: nigrum (NY-grum) (Info)

Synonym:Allium multibulbosum

2 vendors have this plant for sale.

6 members have or want this plant for trade.


24-36 in. (60-90 cm)
36-48 in. (90-120 cm)

6-9 in. (15-22 cm)
9-12 in. (22-30 cm)

USDA Zone 4a: to -34.4 C (-30 F)
USDA Zone 4b: to -31.6 C (-25 F)
USDA Zone 5a: to -28.8 C (-20 F)
USDA Zone 5b: to -26.1 C (-15 F)
USDA Zone 6a: to -23.3 C (-10 F)
USDA Zone 6b: to -20.5 C (-5 F)
USDA Zone 7a: to -17.7 C (0 F)
USDA Zone 7b: to -14.9 C (5 F)
USDA Zone 8a: to -12.2 C (10 F)
USDA Zone 8b: to -9.4 C (15 F)
USDA Zone 9a: to -6.6 C (20 F)
USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:
Full Sun
Sun to Partial Shade

Unknown - Tell us

Bloom Color:
White/Near White

Bloom Time:
Late Spring/Early Summer
Mid Summer


Other details:
This plant is attractive to bees, butterflies and/or birds
Flowers are fragrant
Drought-tolerant; suitable for xeriscaping
Average Water Needs; Water regularly; do not overwater
This plant is resistant to deer
Flowers are good for cutting
Flowers are good for drying and preserving

Soil pH requirements:
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)

Patent Information:

Propagation Methods:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
From seed; sow indoors before last frost

Seed Collecting:
Bag seedheads to capture ripening seed
Allow seedheads to dry on plants; remove and collect seeds

Click thumbnail
to view:

By Todd_Boland
Thumbnail #1 of Allium nigrum by Todd_Boland

By plutodrive
Thumbnail #2 of Allium nigrum by plutodrive

By hortulaninobili
Thumbnail #3 of Allium nigrum by hortulaninobili


2 positives
2 neutrals
No negatives

Gardeners' Notes:

Neutral irishbutterfly On May 7, 2012, irishbutterfly from Nanaimo, BC (Zone 8a) wrote:

I am envious of gardens with this glorious plant. Is it a specific type of onion that blooms or will any onion bloom?
I am new to gardening other than a hanging basket. Thanx, Irishbutterfly

Positive hortulaninobili On Jan 18, 2011, hortulaninobili from St. Louis, MO (Zone 6a) wrote:

Allium nigrum syn. multibulbosum:

One of the many ornamental alliums which provides clean and refined effect in almost any situation. Flowering period (mid-spring) possibly can be extended if planted in a location which receives shade in the afternoon. Never have noticed any pests or pathogens. Growth habit is organized, does not grow out of control, and is simple, fitting in a 'less is more' category.

Allium performs satisfactorily in a regular garden soil with regular moisture and fertility. Organic mulch will prevent bulbs from heaving and keep soil off of foliage. Usually one of the first plants to emerge in my garden (foliage first around mid-February).

Complements other white flowering plants such as alyssum, tulips, light yellow or yellow-green colored narcissi, peonies, flowering sage, or Cheiranthus allionii.

Positive WillowWasp On Jun 6, 2006, WillowWasp from Jones Creek, TX (Zone 9a) wrote:

This is an heirloom Allium that is multi flowering. It has 3-4 inch globes held on thick stems up to 24" in height. The color is white to lilac with green furrows and centers.

Neutral smiln32 On Nov 15, 2004, smiln32 from Oklahoma City, OK (Zone 7a) wrote:

This allium has very thick stems and produces white florets (can be tinged with pink or purple) that rise up from the ground anywhere from 20 - 40". They make a great cut flower.


This plant has been said to grow in the following regions:

Wedowee, Alabama
O Fallon, Missouri
Jersey City, New Jersey
Whitehouse Station, New Jersey

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