Allium ampeloprasum, commonly known as broadleaf or wild leek, is a monocot bulbous perennial native to Europe, western Asia, and northern Africa (USDA GRIN 2011). (The North American wild leek is a different species—Allium tricoccum.) This species is the progenitor of three cultivated vegetables, namely leek or garden leek (A. porrum), elephant or great-headed garlic (A. ampeloprasum var. ampeloprasum), and kurrat (A. kurrat), the Middle-Eastern cultivated leek (Block 2011), which differ in chromosome number but are interfertile. A fourth group, the pearl onion, is also included in this species. (See Wikipedia article in the full entry for a list of other names and varieties.)

The species name is derived from the Greek “ampelo” (vine), and “prason” (leek)—indicating an Allium that grows in vineyards (Block 2011). The Latin word for leek is “porrum,” which is the name assigned by Linnaeus to the cultivated species of leek, and is the root of the French term for it (“poireau”).

A. ampeloprasum does not normally produce bulbs, although in variety ampeloprasum (elephant garlic), it may produce a head of cloves like garlic (A. sativum) but with two sizes of cloves—a bulb of cloves like garlic, surrounded by smaller cloves on the outside or the bulbs may be on short stolons (Brewster 1994).

Horticultural varieties have been selected and developed for different characteristics. In leeks, the leaf bases form long, edible “pseudostems” made of concentric rings of the leaf bases, whereas in the kurrat, the pseudostems are short and the focus is on eating the leaves. Elephant garlic (A. ampeloprasum var. ampeloprasum) is used for the bulb rather than leaves, which typically has a milder flavor than garlic (A. sativum). Although typically with two sizes of cloves, it may produce only a single large clove. This is sometimes confused with the single-bulb cultivar of commerce, but that cultivar, from China, appears more closely related to onion (Allium cepa; Figliuolo and DiStefano 2007). The pearl onion, cultivated primarily in home gardens, is similar to a small leek, but does not have pronounced pseudostem; instead, it produces a cluster of small, almost perfectly round bulbs.

In many Allium species, the flower (often an umbel) produces bulbils, which appear to be small cloves within a bulb. A. ampeloprasum typically does not produce bulbils, although a few varieties may.

Allium ampeloprasum has escaped cultivation in North America and is naturalized in New England and adjacent areas in Canada (eFloras.org 2011), as well as the southeastern states and as far west as Texas, and in California. However, it is not considered particularly invasive, except in Arkansas, where all Allium species are classified as noxious weeds (USDA PLANTS 2011). It is an “environmental weed” in parts of Australia (Groves et al. 2005).