Allium (Alliaceae) 

The genus Allium is large and includes approximately 700 species, plus an equal number of cultivars. Allium comes from the temperate regions of the entire northern hemisphere. In the kitchen, several species are used as vegetables or herbs; the best-known are onion, shallot, leek, chives and garlic. The largest group of allium, the ornamental onions, is used in the garden. One species is suitable for naturalising between shrubs and under trees, the other has striking flowers in the sunny border or can be placed in the rock garden and put in pots.

Unfortunately, the leaves of most ornamental onions turn yellow before the flower has developed properly. That is why ornamental onions are often placed between or behind perennials, which block the view of the ugly leaves. The tall cultivars are also very suitable as cut flowers. The inflorescence can be kept for a very long time in water, but if the vase water is not changed regularly, it will start to smell quite badly, especially in warm weather. All allium species have one thing in common: they spread the familiar onion smell.

The flowering of the ornamental onion consists of many star-, bell- or saucer-shaped flowers that together form a spherical umbel, an oval or a spherical inflorescence at the end of a bare stem. Most alliums are bulbous plants and only a small group has a thickened root, for example leek. The allium species with a bulb can be propagated by sowing or by removing the brood tubers that grow around the old bulb. The other species are also propagated by sowing, but also by dividing the plants. Touching the bulbs can cause skin irritation.

Allium Ambassador, Allium schubertii and Allium sphaerocephalum are good for dried bouquets. Most ornamental onions like a well-drained soil that should not contain too much humus, and a spot in full sun. Plant alliums at the end of autumn. On poor soil it is advisable to dig in some well-rotted stable manure. However, fresh stable and chicken manure are not suitable, because onions do not like it.

Ornamental onions are planted at a depth equal to the size of the bulb. Each individual species indicates whether these guidelines should be deviated from. The small-bulbed ornamental onions can remain in the garden and often naturalise well. Many large-bulbed alliums must be harvested immediately after flowering in the second year and stored at a high temperature (approximately 25°C), after which they are replanted in November. Due to disease, they must then be replanted in a different location.

Allium Cowanii

An ornamental onion that blooms in April-May with bright white flowers that are grouped together in an airy inflorescence on a thin stem. Allium cowanii is a good cut flower that is also sold as such. This lovely bulbous plant is closely related to the Italian garlic, Allium neapolitenum, and is often sold under that name. In countries around the Mediterranean Sea, the Italian garlic grows abundantly in the wild. Plant allium cowanii for a natural look between low grasses.

Allium gladiator

From the grey-green leaves of this cross between allium aflatunense and allium macleanii develops an almost 140 cm long flower stem with a spherical, compact inflorescence. In this Allium Gladiator too, the star-shaped flowers change from a light purple to pink hue. The flowering of this giant falls in May and June. It is a good cut flower.

Allium Karataviense

This ornamental onion 'Karataviense' has a stocky appearance. Between the broad, grey-green leaves a sturdy, 10 to 25 cm high stem develops with a spherical inflorescence at the end with 50 or more soft pink to white, star-shaped flowers with a fine purple stripe in the middle of the leaves. The leaves of this ornamental onion remain good longer than those of most other species. A spot in a low ground cover, such as the Acaena or in the beautiful turf-forming, grey-leaved Raoulia, is recommended. This Allium is suitable for the rock garden and is certainly also suitable for being placed in a pot. 'Album' is a beautiful, white-flowering cultivar.

Allium moly (Goudlook)

A beautiful and easy to grow yellow flowering ornamental onion that is also called golden garlic Allium 'Moly'. The relatively large star-shaped flowers are close together on 15 to 24 high stems. The lanceolate grey-green leaves remain beautiful for a long time. It can stand in both sun and light shade and naturalises very well there. In its area of ​​origin, south-west France and eastern Spain, it is often found in forests in dry, but also somewhat moist places. The cultivar Jeannine is richly flowering, because the bulb always produces two flower stems.

Allium ‘Mount everest’

Among the large-flowered and long-stemmed ornamental onions, there is very little white. You may have already deduced from the name that the Allium ‘Mount Everest’ is an exception. The leaves are beautifully shaped and remain green for a long time. The flowering stem is approximately 120 cm long. The spherical inflorescence has a diameter of approximately 15 cm and is made up of dozens of white, star-shaped flowers with slender petals and a green ovary in the heart. It is a good cut flower.

Allium schubertii

A very special Allium and then we are talking about the inflorescence, because the leaf, like with so many ornamental onions, is not very attractive. With Allium schubertii it is broad and bright green, but is already on its way out when the flower starts to bloom. The bloom is a bit like fireworks that have just burst; the flower stems have a diameter of no less than 30 to 40 cm. The flowers are unisexual or hermaphroditic and the male flowers have longer stems than the female ones. The star-shaped flowers are lilac-pink, fading to a slightly lighter pink. The flower stems are warm pink. It is a good cut flower, both fresh and dried. The bulb is sensitive to severe frost and must therefore be protected with a winter cover.

Allium Spaerocephalon

This ornamental onion (Allium Spaerocephalon) originates from Central and Southern Europe. The name bulbous onion reflects the nature of the inflorescence; sphaerocephalus means bulbous. On the sturdy, thin stems that are about 70 cm long, there is a very compact, oval inflorescence, so compact that this ornamental onion is also called a drumstick. The reddish-purple flowers develop from the green buds in June-July. It is a very nice ornamental onion that does very well in the perennial border. It can also grow wild in grassland, in such an unmown grassland, intersected by mown paths and situated between fruit trees, as is so often seen in English gardens. The leaves are not very attractive, so this ornamental onion should be planted between other plants. Plant quite a few together because then it will get the attention it deserves. This Allium is also an excellent cut flower and is sold as a bare bunch of 'drumstick'.