Family: Amaryllidaceae
Common name: Giant onion, Giant Ornamental Onion, Ornamental Onion
Giant allium is a beautiful garden plant with large globular flowers, standing tall in flowerbeds or pots. They are native to Central and South Asia and can grow well in a wide range of climatic conditions.
Plant Characteristics
Giant onion plants can grow to a height of 1 to 1.5 meters because of the tall flower clusters that are held aloft on straight, sturdy stems. Leaves are only 30-60 cm long growing directly from the roots.
Giant onions that aren’t flowering are usually not noticeable since the leaves are quite short and nondescript. They are glossy green and slightly arching to the ground, and most of the leaves wither before the flowers start to bloom.
Once the Giant onions start blooming, they become the centerpiece of your garden with their large, lofty, dramatic flowers that bloom as a large ball about 15 cm in diameter.
These interesting balls are made up of numerous small star-shaped flowers that are initially green, turning lilac as they mature. Flowers have six distinct petals and a green, bulbous center.
Flower stalks that extend from the center of the spherical structure to the petals is reddish in color.
During late spring to early summer, the Giant onions burst out into a colorful, architecturally-splendid, purple display standing out against the greenery of your garden.
These plants thrive on flower beds and in pots, attracting insects, bees, and butterflies. After pollination the flowers produce small capsule-like seeds which contain small black seeds which are typical of the Onion family.
Gardening Tips
Giant onions grow well in good sun and well-drained soil. They need to be watered and fertilized regularly during the growing season when shoots are emerging. Water when the soil is dry to touch, every day or every alternate day and fertilize once in 2-3 weeks for optimum results.
Tall stalks growing in windy areas might need staking or support. Remove spent flower heads if you do not want excess seed production.
Though they belong to the Onion family, all parts of this plant contain sulfides which are toxic to humans and pets. So it is best to keep them away from pets and small children since ingestion of leaves or flowers may lead to nausea and vomiting.
These plants are pest-resistant and are not eaten by grazing animals because of the strong onion smell.
Propagation
Propagation is through seeds or by dividing roots when the parent plants form great, big clumps. In fact, it is advisable to divide them every 3-4 years to prevent over crowding.
Photographed at: KEW gardens, London
