Flowers GrowingYour personal florist | All about flowers, gardening, plants, arrangements, flower shops

Tall onions grown for garden display are bulbous perennials from the Allium genus; their attractive flowerheads look excellent in a mix border, especially grouped together. The tiny summer flowers are usually massed into dense, rounded or hemispherical heads – like those of Allium giganteum – on they may hand loosely, like the yellow flowers of Allium flavum. When crushed, the strap-shaped leaves release a pungent aroma; they are often withered by flowering time. The seedheads tend to dry out intact, standing well into autumn and continuing to look attractive. Some allium self-seed and will naturalize.

The gardeners who want to obtain amazing home gardens mix ornamental onion, like Allium bollandicum “Purple Sensation” or Allium cernauum “Hidcote” with pink or purple-flowering perennials such as iris, lavender, salvia, peony, hardy geranium and ornamental grasses such as blue oat grass, blue fescue and fountain grass.

How to grow ornamental onions

The ornamental onions grow in fertile, well-drained soil in full sun to simulate their dry native habitats. Plant bulb 5-10 cm (2-4 in) deep in autumn; divide and replant older clumps at the same time or in spring. In climates with cold winters, provide a thick winter mulch for Allium cristophii and Allium caeruleum.