Allium sativum, commonly known as garlic, is a species in the onion genus, Allium.
Its close relatives include the onion, shallot, leek, chive, and Allium chinense. With a history of several thousand years of human consumption and use, garlic is native to the region between the Mediterranean and China, and has long been a common seasoning worldwide. It was known to Ancient Egyptians, and has been used both as a food flavoring and as a traditional medicine.
Allium sativum is a bulbous plant. It grows up to 1.2 m (4 ft) in height. Its hardiness is USDA Zone 8. It produces hermaphrodite flowers. It is pollinated by bees and other insects.
Allium sativum grows in the wild in areas where it has become naturalized. The “wild garlic”, “crow garlic”, and “field garlic” of Britain are members of the species Allium ursinum, Allium vineale, and Allium oleraceum, respectively. Identification of the wild progenitor of common garlic is difficult, due to the sterility of its many cultivars which may all be descended from the species Allium longicuspis, which grows wild in central and southwestern Asia.
In North America, Allium vineale (known as “wild garlic” or “crow garlic”) and Allium canadense, known as “meadow garlic” or “wild garlic” and “wild onion”, are common weeds in fields. So-called elephant garlic is actually a wild leek (Allium ampeloprasum), and not a true garlic. Single clove garlic (also called pearl or solo garlic) originated in the Yunnan province of China.
Garlic is easy to grow and can be grown year-round in mild climates. While sexual propagation of garlic is possible, nearly all of the garlic in cultivation is propagated asexually, by planting individual cloves in the ground. In colder climates, cloves are planted in the autumn, about six weeks before the soil freezes, and harvested in late spring or early summer. The cloves must be planted deep enough to prevent freeze/thaw, which causes mold or white rot.
Garlic plants can be grown closely together, leaving enough space for the bulbs to mature, and are easily grown in containers of sufficient depth. Garlic does well in loose, dry, well-drained soils in sunny locations, and is hardy throughout USDA climate zones 4–9. When selecting garlic for planting, it is important to pick large bulbs from which to separate cloves. Large cloves, along with proper spacing in the planting bed, will also improve bulb size. Garlic plants prefer to grow in a soil with a high organic material content, but are capable of growing in a wide range of soil conditions and pH levels.
There are different varieties or subspecies of garlic, most notably hardneck garlic and softneck garlic. The latitude where the garlic is grown affects the choice of type, as garlic can be day-length sensitive. Hardneck garlic is generally grown in cooler climates and produces relatively large cloves, whereas softneck garlic is generally grown closer to the equator and produces small, tightly-packed cloves.
Garlic scapes are removed to focus all the garlic’s energy into bulb growth. The scapes can be eaten raw or cooked.