Leek Identification

Leaves

• Leeks grow broad, flat leaves that alternate from side to side, forming a distinctive fan shape in mature plants. The leaves are usually some variation of yellow-green, ranging to a darker blue-green depending on the variety. The leaves of young leek plants superficially resemble those of green onions, but may be differentiated by cutting off a short section crosswise -- an onion leaf section forms a hollow ring, whereas leek leaf sections are solid and flat.

Stalk

• Leeks are unusual among members of the onion family because they do not form bulbs even when mature. Instead, the stalk of the leek remains cylindrical, but increases in diameter as the plant grows new leaves. The stalk is formed from the tightly wrapped bases of the leaves. Most growers pile soil around the stalk to keep it white. Unlike other onions, the stalk has a tendency to accumulate sand and grit between the interior layers, which must be carefully rinsed out before cooking the plant.

Flowers

• Leeks do not form flowers or seeds during their first year. Growers generally harvest them either during the fall of their first year or the spring of their second year, but if the plants are left until their second summer, they send up a solid, cylindrical stalk up to 48 inches tall that opens into a spherical purple, pink or white cluster composed of many small flowers. The flowers eventually form seeds capable of growing into new leek plants.

Wild Leek

• Wild leeks are members of a different but related species that grows wild in forests throughout eastern and central North America. These plants form clusters of wide, flat green leaves growing from an underground bulb. Both the leaves and bulbs smell strongly of onions when crushed and are edible. The plants bear single flower stalks with an umbel of white flowers that appears in summer after the leaves begin to die back.