Giant onion - Allium giganteum (Care, Characteristics, Flower, Images, Toxic)

Giant onion

Also known as: Ornamental onion

Giant onion, Allium giganteum, or ornamental onion, is a member of the Amaryllidaceae family. This hardy perennial grows large purple clusters of tiny florets. It’s the largest of the ornamental onions, and although it produces onion-like fragrances, it is not grown for consumption.

Scientific classification

Species

Giant onion (Allium giganteum)

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Toxic to Humans

Toxicity

Perennial, Annual

Lifespan

Herb

Plant Type

Summer

Bloom Time

Mid summer

Harvest Time

50 cm to 60 cm

Plant Height

20 cm

Spread

Green, Gray, Blue

Leaf Color

15 cm to 20 cm

Flower Size

Green

Fruit Color

Purple, Pink, Violet

Flower Color

Green

Stem Color

Moderate

Growth Rate

Images of Giant onion

Distribution of Giant onion

Distribution Map

Giant onion is native to Central and South Asia, thriving particularly in temperate zones. It has been introduced and is cultivated in other regions across the world, adapting to a variety of climates outside its native range. Notably, giant onion is widely valued and can be found in ornamental gardens in the temperate regions of the globe.

Native

Cultivated

Invasive

Introduced

No species reported

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Habitat

Cultivated Beds

Hemisphere Trend Curve

Northern

Sorthern

Culture

Garden Use

Giant onion is tall with large flower heads, so it is perfect for dried or cut flowers. Its use in borders and beds creates height and a striking aesthetic, making it suitable for cottage and informal gardens. Giant onion is highly attractive to butterflies, has fragrant blooms and foliage, and is relatively deer resistant.

Symbolism

Unity, Humility, Patience

Name Story

Giant onion: Giant onion is also known as Allium giganteum. Allium is the Latin word for garlic. Giganteum is the Latin word for great. Together, the words explain the common name for this plant, giant onion. It certainly resembles a giant onion with its tall spikes and giant balls of purple blooms.

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Cultivars

There are several recognized cultivars of Giant onion, including the following common varieties :

Onions 'Powder Puff'Onions 'Globemaster'Onions 'Jackpot'Onions 'Beau Regard'Onions 'Ambassador'Onions 'Pinball Wizard'

Toxicity

Giant onion is toxic to humans, cats, and dogs if ingested. Symptoms in humans include diarrhea, vomiting, and nausea, especially in children. For cats and dogs, ingesting any plant part leads to poisoning, causing gastrointestinal upset and lethargy. Immediate veterinary care is crucial for pets showing signs of toxicity after consuming giant onion.

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Quickly Identify Giant onion

Majestic umbel with vivid pink florets clustered tightly atop a leafless stalk.

Small, star-shaped purple flowers with six-parted petals in a 5-6 inch cluster.

Long, slender, strap-like leaves with a green color and garlic-onion fragrance.

Sturdy, upright stem reaching 3-4 feet with unbranched growth, supporting large flowers.

Leaves typically lie flat at the plant's base, exhibiting a bluish-gray tinge.

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Care Guide for Giant onion

Every week

Water

Full sun

Sunlight

20 - 38 ℃

Ideal Temperature

Garden Soil

Soil Type

Water: Giant onion originates from temperate climates and prefers consistent moisture while being drought-resistant. Weekly watering supports its health. Typically grown outdoors, giant onion thrives in well-draining soil to prevent excess moisture, especially during wetter months, preserving bulb integrity.

Fertilize: For optimal health, use balanced fertilizers with equal NPK ratios in spring and high phosphorus before bloom for giant onion. Fertilize monthly until summer's end, diluting to half-strength. Avoid applying during dormancy, incorporate into soil, and adjust frequency post-bloom for robust year-round growth.

Pruning: Prune giant onion in early spring by removing dead foliage and spent flowers to enhance growth and maintain vigor. Cut at the base for fresh leaves. This practice improves aesthetics, boosts air circulation, and prevents diseases, supporting healthier blooms.

Propagation: Propagate giant onion in Spring using tubers for best results. Successful propagation is marked by new shoots. Proper tuber storage and correct planting depth are essential for optimal growth.

Repotting: Repot giant onion in early spring every 2-3 years before growth begins. This erect perennial features spherical blooms. Use a deep pot for its extensive roots, ensure well-draining soil, and maintain consistent watering to prevent stagnation, promoting recovery and robust growth.

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