The vegetable leek is a cultivar of Allium ampeloprasum, the broadleaf wild leek. In the past, many different scientific names were used to identify various species of leek, but now they are all classified as cultivars of Allium ampeloprasum. The part of the plant that can be eaten is at times erroneously called a stem or stalk. This part is actually a bundle of leaf sheaths. This bundle is blanched by putting soil around it (so-called ‘trenching’). The plant is usually sold as a small seedling and planted in a greenhouse. Later on, as weather permits, the leek is planted outside in the soil. Once outside, the plant is rather hardy and many varieties can be left in the soil during winter and harvested when there is a need for them.