Allium Mount Everest or 'ornamental onion' is a striking herbaceous perennial known for its tall stems and dramatic spherical flower heads. From late Spring to early Summer, it produces large, pure white globe-shaped blooms made up of tiny star-like flowers. These elegant blooms rise above lush green foliage, adding structure and height to borders. Loved by pollinators, Mount Everest brings visual drama and wildlife support to the garden. Reaching up to 120 cm in height, these stately blooms return year after year in UK gardens.. Plant Allium Mount Everest bulbs in Autumn to early Winter in fertile, free-draining soil in full sun. Space them around 10cm apart and plant at a depth of three to four times the size of the bulb. Water well after planting and add mulch or compost to improve drainage. After blooming, remove any spent foliage and cut stems back once flowering finishes. Fully hardy in the UK, they naturalise well and return each year with minimal care.. Ideal for flower beds, herbaceous borders, and gravel gardens, these tall alliums create impact when planted in groups or dotted through mixed schemes. They pair beautifully with ornamental grasses, perennials, or darker-flowered alliums for contrast. Suitable for patio containers too, and also make excellent cut flowers.