Onion or Shallot – who cares?
There are several flavour groups in the modern kitchen. One of these is the onion group which includes, onions, leeks, chives, garlic and, shallots’. Excluding garlic the flavours are very similar and seem to be variations in strength of the onion taste. There are dozens of cultivars of each of these common groups. The characteristics of each cultivar are more to do with color, size, shape and harvest time than actual flavor.
The genus is quite large with 200 plus (some say 900+) species all of which have flowers that are produced on scapes. It is a monococt which means that it has long blade or tube like leaves witn parallel venation. Most produce rhizomes or bulbs from which the elongated leaves grow during spring to autumn. Most like a full sun position in a well drained soil although there are some species that are tolerant (or even prefer) heavy to wet soils in part to full shade.
The genus is mostly from the northern hemisphere although there are a few from Africa and Sth America. Various species have been cultivated for in excess of 1000 years. There are a few toxic varieties/species but for most, all of the plant is edible. Almost every cuisine in the world uses an Allium cultivar or two in their daily diet. Most have a strong sulphide content which makes them beneficial to a healthy life style. The benefits are related to the particular species and cultivar.
Like a few other large edible genera Allium is widely grown around the world under a myriad of common names. Unfortunately the Latin names are also quite mixed up. They are divided into several groups the ‘garlic/leek group and the ‘onion group’. One of the worst cases of confusion is in the onion group, between the different types of shallots and the various forms of bunching onions. A problem exacerbated by the inconsistent naming used by the chain stores and the fruit and vegetable industry.
There are three main onion species: Allium cepa – the common onion and its relatives, Allium fistulosum – bunching onion and its relatives, and Allium ascalonicum – the French shallot and its cultivars. There is also the hybrid between A.cepa and A.fistulosum called A. x proliferum.
All of these species have a myriad of cultivars and hybrids with a huge number of common names that are used, almost randomly across the three species. The names have a strong correlation to the country of origin and seem to bridge across the different species.
This is a good example of why we shouldn’t use common names but also demonstrates the problem of putting Latin names on highly crossed and very similar edible plants. The main ‘onion’ varieties are:
A. cepa This is the cultivated form of the wild onion that is believed to have been grown for over 7000 years. In general it is a perennial that is usually grown as an annual. It has long green foliage and produces a single bulb with a dry skin like outer layer.
A. fistulosum This covers the group of plants commonly known as bunching onions and generally refers to varieties mostly grown in Asia. They don’t have a fully formed bulb and are also known as scallions. Other names include Welsh Onions, Bunching Onion, Japanese Red Onion and Spring Onion (in some countries these are the common name for juvenile forms of other species).
A. cepa aggregatum This species (syn: A. ascalonicum) cover the varieties commonly called shallots. The cultivars all produce bulbs that are more like garlic than onion in the growing habit. They have the classic onion colour and dry ‘skin’. The flavor is also similar but much sweeter.
A. x proliferum This unusual form is a cross between A. cepa and A. fistulosum. There aren’t many cultivars. The main form is referred to as Walking Onion or Tree Onion due to its habit of producing small bulbils on the flower stems that then bend over and take root.
Then there are few common other Alliums:
A. schoenaprasum This species covers the common chives that are widely grown around world. They have round hollow leaves and form a tuber like growth from which the new leaves grow away in spring after either dying off or slowing down over winter.
A. tuberosum Thus variety is known as Garlic Chives or Chinese chives. They are larger than common chives, have a subtle garlic flavor with large solid and flat leaves. Like common chives this variety also produces a tuber like root growth.
A, sativum The common garlic. There are two basic forms – soft and hard necked. Produces a large ‘globe; in mid-summer that consists of one to 20 cloves (depending on the variety) which can be harvested and eaten or used to produce new plants in the following autumn.
A. ampeloprasum This species covers the common leek and several cultivars like the giant or Russian garlic. The latter is a bulbing form of the household leek, all of which have long flat strap like leaves.
By going back to basics the differences are quite obvious. However using common names can be very confusing. This is the aggravated by the fact that one of the main common names; Spring Onion is used to describe any small green onion with tall green foliage and narrow non bulbing stems – often due to juvenility rather than genetic growth habit.
To conclude, Spring Onions or Scallions are technically narrow onions with green foliage and red or white skinned swelled stems that do not bulb. Shallots are onion like bulbs that form and multiply in a similar manner to garlic and onions are the tall growing semi-perennial plant with medium to large bulbs that are the swollen bases of the green white stems. Leeks are the tall growing plants that produce thick white stems and chives are the small thin leaved semi deciduous perennials. However don’t take any pub bets as they will not be easily resolved.