Ornamental Onions – Allium

Ornamental Onions they are called and they certainly carry the distinct onion scent. There are upwards of a hundred species, many being exceptionally colourful in the border throughout early summer. They like a sunny position and any ordinary well-dug border soil is suitable. They are useful plants for a dry, sandy soil, in fact, it is in such a soil that they are at their best.

PLANTING

The first week of November is the best time, when the bulbs should be planted 3 in. deep. A little sand sprinkled around each bulb will be appreciated. The taller forms should be planted towards the back of a border or to the front of a shrubbery – the dwarf forms are most suited to the rockery. They are ideal flowers for the labour-saving garden in that they may be left completely untouched for many years before they need to be lifted and divided.

Ornamental Onions

SPECIES

  • Allium albopilosum. Producing its heads of star-like flowers of pink during June on 2-ft. Stems, this species received an Award of Merit from the Royal Horticultural Society in 2003.
  • A. anceps. A very dwarf species bearing rich pink flowers on 6-in, stems during August. This is a valuable late-summer rockery plant.
  • A. avireum. Bears rush-like leaves and large ball-shaped heads of sky-blue flowers on long stems during June. A very hardy species from Siberia and useful for cutting.
  • A. Karataviense. From Afghanistan and a suitable rock-garden plant. Produces its lilac flowers throughout May, but its chief claim to beauty lies in its grey, crimson-tinted foliage.
  • A. moly. The best species for naturalizing in grass or the shrubbery for it increases rapidly, rather too quickly perhaps and so should not be planted too near other choice bulbs. Called the Golden Garlic, its compact bright yellow heads are produced during June.
  • A. neapolitanum. A grand cut flower for it bears pure white sweetly scented flowers on 2-in. stems during early summer. A. umbellatus. The hardiest of the agapanthus and a flower most suitable for cutting. There is no need to lift this species. It should be planted in beds given the protection of a wall or hedge where the bright blue flowers may be used for cut bloom. The species albus, of purest white is also very lovely when cut.
  • A. Ostrowskianum. Probably the best of all the alliums for it produces its compact heads of deep lilac blooms on 6-in, stems, rather like Primula denticulata.
  • A. pulchellum. Another valuable August flowering plant when it bears its deep violet heads on a-ft. Stems.

Beautiful Onion – Allium pulchellum

For those who do not recognize this Onion, to see it in full bloom can be a puzzle of identification. A large patch of them will present a haze of light purple, each plant throwing up a tall spike carrying a tassel-like flower quite unlike any other. When they first open, the flowers arch down from the head like a fountain of fireworks, but once they are fertilized and the seed begins to form, the individual flower stalks become erect, so there are always some pointing up and some splaying outwards: a very attractive combination.

One of the problems of its habit of being late-flowering is that its leaves and stem are in evidence for some time before the flowers appear. This would not normally be a problem, except that those of A. pulchellum look just like blades of grass and to the undiscerning, a border full of this Onion can look unweeded.

This is an attractive Onion, but like many things of beauty, they can also have an ugly side. In this case, it is the tendency to spread. It is a prolific seeder and will self-sow all over the garden given a chance. Not only that, but it will also produce masses of bulblets and these can easily get spread around. Some gardeners ban it altogether because of its invasiveness, while others think that the beauty of the plant makes it worth the inconvenience. Deadheading immediately after flowering helps to prevent the self-sowing.

The Beautiful Onion has a graceful, wispy appearance when viewed at close quarters.

This plant’s soft, misty appearance allows it to mix well with many other plants in herbaceous or mixed borders. It does particularly well with other purples.

Plant bulbs in Spring or Autumn. Avoid planting in regular rows, but use a scattered, natural pattern. Try planting around other plants that have an earlier flowering season.

Like most Onions, they prefer an open, sunny situation, although they will occasionally self-sow in light shade.

A mass of these bulbs in flower produces a haze of purple across a border.

These plants rarely need any extra water.

Cut back after flowenng. To prevent seeding. If it becomes congested, lift and transplant or discard some of the bulbs.

Some botanists classify this as a subspecies of A. cahnotum; it is sometimes seen as A c. pulchellum.

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