When I was growing up few herbs would grow in my chilly zone 3(-40c or f) city. One daring plant which survived quite nicely was a member of the Allium family and bloomed with mauve papery flowers. Later I saw wild Allium growing along the banks of the Fraser River near Lytton. Here there are not only wild species of Alliums but many ornamental types growing in gardens and parks. One group which catches everyone’s eye are the Giant (flowering) Onions.
There are nearly 900 species of Allium with about 150 of them coming from Turkey, and 40 from the California area. Giant Onions are often a natural, accidental or planned crossing of species. Some of the many species which lend their attributes such as height, color and flower density include giganteum, hollandicum(aflatunense), cristophii, macleanii, karataviense . Many named varieties have been selected, the process is slow and can take up to 20 years before they ready too be sold to the public.
The first Giant Onion which was seen in gardens was its namesake Allium giganteum which can grow up to 1.8m(6ft) tall and did really create a sensation. It has been found that such large flowers on wiry stem are susceptible to wind damage and are really too big for most gardens. From this time there have been growers busily crossing species to create shorter plants with large flowers and preferably nicer leaves. Most Giant Onions are between 45cm -1.2m(18-48in) tall.
No one can not be impressed with these stately and impressive flower displays. Giant Onions are very versatile as plants which is why they are so often seen in public gardens. If you like butterflies and bees these are great magnets for them. The tiny flowers actually are fragrant and I don’t mean in an oniony way.
We are lucky to have the opportunity to grow these wonderful plants. Giant Onions want the simple things in life, full sun, fertile soil which is well-drained and water in the spring and early summer when they are growing their most vigorously. They offer the most impact when planted in groups. Plants these bulbs in the early fall. They should be planted 10-15cm(4-6in) deep and should be spaced the same distance apart. They can take a fair amount of cold down to a chilly -20c(-10f) or rated as zones 6 through 10. In colder regions you can lift and store the bulbs over winter.
Giant Onions are drought tolerant, great for here where we have several months over the summer and fall with little rain. Another notable thing which is useful about them is that deer and rodents are said to not like them. These plants slowly multiply, so you can lift them after several years and divide them.
Giant Onion flowers are great against many types of other foliage, blue-green, burgundy, chartreuse, gray and just plain green become wonderful backgrounds and I have seen many inspiring color combinations. I am sure you can think up some stunning combinations for your garden.
On the great Allium hunt:
A good listing of species and forms are found here: http://www.pacificbulbsociety.org/pbswiki/index.php/BigBallAlliums
Wiki has lots of interesting information on Alliums: http://en.wikipedia.org/wiki/Allium