Leeks grow straight up from the ground, the flat leaves growing up from a cylindrical, rounded bulb, overlapping each other in a concentric pattern. Many growers pile dirt around the nearly one-inch base bulb, to lengthen the white portion of the bulb by limiting sunlight and therefore chlorophyll production. Because of this practice, Leeks collect a lot of dirt between their leaves. The tops of the leaves, referred to as ?flags,? are dark green with a bluish tint, and tough. They fan out at the top of the stalk, like the fronds of a palm tree. The flat Leek leaves can grow up to nearly a meter in height, the bulb sitting shallow in the dirt, around 8 centimetres (3 to 4 inches) long. The edible part of the leaf stalk averages of 30 to 35 centimetres (13 inches) in height, up to 5 centimetres in diameter, and is a light green colour. Leeks have a flavour that is milder than an onion, with a slight sweetness.