Leeks have recently gained popularity in the vegetable world, but they’re still not filling the serving dishes of ordinary households as frequently as other veggies.
Much favors the cultivation of the leek: They are relatively easy to grow and are tough once established, they are not eaten by four-legged mammals, they last well into the fall, and they can be overwintered in many colder climates with simple protection. While subject to a number of diseases and the attention of a variety of insects, they are generally free of serious problems depending on climate and weather. Leeks do best in rich, moist soil and require a fairly long growing season. In my opinion, the biggest drawbacks to growing leeks are that seeds need to be started early and indoors, and it is often difficult to find plants for sale, especially heirloom varieties.
Leeks (Allium porrum) are a member of the Allium or Onion group. They are monocotyledons, so they have a single “seed leaf” and the leaf veins are parallel to each other. Most members of this family are perennials, forming a rhizome or bulb, and some, like leeks, are biennials, producing seeds in their second year of growth.
Compounds in leeks
All alliums possess a variety of organosulfides, which are converted to a wide complex of sulfur compounds when the plant parts are bruised, cut or chewed. This results in the plants’ distinctive odor and flavors, as well as the stinging and irritation when the plant is touched or consumed. The compounds remain in an inert state in the plant until they are released. While some of these compounds are quite potent, most are relatively short lived and begin to degrade in the environment and plant tissue once released, and especially with heating. Because many of these molecules are so volatile, they can quickly diffuse in the air and, in the case of onions, cause our eyes to tear.
Leeks (Allium ampeloprasum var. porrum) possess less potent compounds than some of their cousins and a different array of compounds to create their unique taste. At last count, leeks contained about 90 different flavor compounds. The edible whitish portion of the leek is considered a false stem or elongated bulb.
A close relative that forms a true bulb is elephant garlic (Allium ampeloprasum var. ampeloprasum). It is milder in taste than garlic, and more garlic-like in taste than leeks. Kurrat (Allium ampeloprasum var. kurrat), known as Egyptian leek, is grown primarily for its leaves. Kurrat is not hardy in cold climates.
History of cultivation
Leeks are an ancient crop, grown and consumed prior to 3000 B.C. in Sumeria. They are depicted in Egyptian tombs of the Early Dynastic Period, although they were probably cultivated earlier in Egypt. Ancient archeological sites show evidence of dried leek specimens, probably kurrat. The cultivated leek, like many domesticated plants, is unknown from the wild. Leeks are thought to have originated in the Middle East. A passage in the Bible refers to leeks, although it is possible this may be its close relative kurrat. Leeks are still widely cultivated today in Israel.
In ancient Greece, leeks were called prason, while in ancient Rome they were known as porrum. Ariccia in central Italy was recognized for its leeks, according to the naturalist Pliny the Elder, who said the best leeks came from Egypt. Roman Emperor Nero favored leeks, consuming them to clear his throat and earning him the nickname, Porrophagus (“leek eater”).
Precisely when leeks arrived in northern Europe is unclear; the Romans could have introduced them, and they were widely grown by the Middle Ages. In the Plan of St. Gall, an idealized monastery complex of the 9th century, leeks were part of the garden plan. They may have been in Wales by the 7th century, where they figure prominently in Welsh history and legend. Supposedly Cadwaladr, the Welsh king of Gwynedd, instructed his troops to wear leeks on their hats in order to distinguish them from soldiers of the Saxon army during battle. Ultimately the leek became one of the Welsh symbols. On St. David’s Day, celebrating the patron saint of Wales, Welsh people wear leeks, and reputedly there is a surviving tradition that soldiers of Welsh regiments eat a leek on St. David’s Day.
Leeks became an important if minor crop throughout northern Europe. They are a component of one of the traditional French country soups, and, in France, they were sometimes referred to as l’asperge du pauvre, poor man’s asparagus. However, they are the foundation of the well-known Vichyssoise, a leek and potato soup traditionally served cold. In 1917, Chef Louis Diat of New York’s famed Ritz Carlton reminisced about a hot soup his mother served him that she cooled down for the children with the addition of milk. This inspired him to create the cold Vichyssoise, named after the commune in central France in which he grew up, Vichy.
Leeks were grown in North America by the late Colonial period. In 1804, Bernard McMahon lists the Broad London Leek in his broadside catalog. The listing was an improvement from the common leek, sometimes known as the Flanders or narrow-leaved leek, with leaves arranged around the stem, and not to be confused with the later Broad London Flag Leek.
The flag leek was the next major improvement, as it produced more substantial stems with leaves arranged on two sides of the stem. These became known as Scotch leeks, represented by the Musselburgh Leek and supposedly developed by Dutch immigrants in Scotland in the late 18th century and named for the town of Musselburgh, Scotland. By the 1830s, these leeks were widely available. In 1885, the seed company Vilmorin described eight varieties of leek cultivated in France.
Musselburgh or Scotch Flag is still available today and well worth growing. It has relatively long, thick stems and substantial broad leaves that spread fanlike. It is an improved form of Common Long Winter Leek.
Carentan, or Monstrueux de Carentan (Giant of Carentan), is a great old variety originating in France. When grown in moist, fertile soil, the stems can be quite thick in girth, and the edible portion can reach 6 to 8 inches in height.
Broad London Flag is another excellent variety, producing long stems 2 inches in diameter with medium-green foliage. It is also offered under the name American Flag, which first came into usage in the 1930s. It appears to be identical with Broad London, although some catalogs also call it Musselburgh.
Another tall variety is Prizetaker or Lyon, an English variety introduced by 1885. This is a reliable and productive variety with dark green leaves, thick stems and good taste, often grown for exhibition. This variety, while not early at 135 days, is considered earlier than Broad London.
While there is definite variation among the physical characteristics of leeks, I think the flavor is fairly consistent. Crops like onions have some advantages over leeks in their ease of preparation, price, and amount of useable plant, yet there is no other crop that has the great flavor of leeks. If you are not growing them, you should be — or you should at least be eating them.
He's an expert on heirloom vegetables, and a seed preservationist with an avid interest in herbs, spices, food, cooking, kitchen and ornamental gardens. His newest project revolves around sacred tobacco and its redistribution to native peoples. You can find him on Google+.