One of the most beautiful sections of a garden I have ever seen was the Laburnum Walk created by renowned English garden designer Rosemary Verey OBE in her own garden at Barnsley House. The laburnums were hanging with long, pendulous racemes of yellow blossom, contrasting with the underplanting of numerous ornamental onions, known as Allium Globemaster with their spherical violet-purple flower heads. The sight was absolutely stunning.
October is the perfect month to get alliums planted so you can enjoy these imposing flowering umbels in your garden next May and June. Due to their ease of propagation, provided you have fertile, well-drained soil and a sheltered sunny location, these ornamental onions are ideal for novice gardeners.
Alliums are truly versatile plants to grow as they work in a variety of garden styles from contemporary planting schemes to full blown cottage gardens. The larger ornamental species are perfect in borders and pots, whilst smaller varieties do well in raised beds, containers and rock gardens. They are most effective when planted in groups. Additionally, some of the larger flower heads dry well so can be used for flower arrangements.
When planting the bulbs, plant to a depth twice their diameter and cover with soil. They can be left undisturbed for several years but if you do need to lift and divide, do so as soon as they have died down after flowering. If old flowerheads are left on the plants, some species will happily self-seed. Due to their colour, varying from dark purple to blue and even white and yellow, with good pollen and nectar values they are attractive to honeybees and wild bees, giving you another reason to use one or more varieties in your planting scheme.
Top picks when selecting ornamental Alliums:
Allium giganteum, blooming June to July these can reach a height of 1.5m with flower balls up to 12cm in size. This variety is best planted as a stand alone or in groups of up to five bulbs.
Allium cristophii, (Star of Persia) has the largest flower spheres reaching a diameter up to 25cm. The purple, star-shaped individual flowers dry well as the petals hold up when dried. The plants reach a height of 20-40cm and should be planted with spacing between bulbs from 30-50cm.
Allium Gladiator, another variety with larger flower heads up to 20cm across, this time bearing clusters of light lavender-purple flowers. Stems grow up to 1m high, with leaves dying back at flowering time.
Allium Globemaster, a popular choice, with deep-violet flower heads up to 20cm across and stems up to 80cm tall. Foliage dies back before flowers emerge, so best interplanted with other lower-growing perennials.
Allium schubertii, a spectacular variety to consider. Growing up to 60cm tall, it bears umbels of 50cm or more striking, star-shaped pink-purple flowers with a starburst effect which can extend to 30cm across in early summer. These are also an excellent choice for dried floral arrangements and decorative use.
Allium atropurpureum, provides maroon-purple flowers around 5cm across with stems up to 50cm. This variety works well when scattered amongst ornamental grasses and wild meadows where it will happily naturalise.
Allium siculum, this particularly unusual variety looks different to other alliums. Stem height can reach 1.2m with a terminal umbel of long-stalked, nodding bell-shaped flowers combining cream, pink and pale green tints. Works well in a mixed border or wilder more natural garden interplanted with ornamental grasses, they dry to erect seed pods in late summer.
Allium sphaerocephalon, attractive to pollinators, these have an unusual dense green drumstick flower head, maturing to maroon-red. This variety also works well in gravel gardens. Grows to a height of 90cm with a small flower head.
Allium Caeruleum, if you are looking for blue rather than purple alliums, these offer stunning bright blue flowers up to 5cm across on upright stems growing to a height of 50 to 80cm.
Three white-flowering varieties:
Allium stipitatum (Mount Everest) is a taller variety, growing up to 1.2m and bearing fifty or more white, star-shaped flowers up to 12cm across. A wonderful contrast when planted in groups along with purple flowering varieties.
Allium nigrum (black garlic) produces striking white flowers with distinctive dark green or greenish black centres. Stems reach up to 80cm with flowers forming round clusters with a flatter top up to 7cm across. Excellent for cutting and drying.
Allium Graceful Beauty, as its name suggests really is quite beautiful. Reaching a height of up to 30cm, its flower heads are around 7cm comprising masses of star-like white blooms, each with pointed petal and delicate purple anthers, giving a subtle hint of colour. This variety is ideal for planting in containers or at the front of a border.
Alliums are widely available in garden centres, and from online specialists including peternyssen.com and taylors-bulbs.com.
