Used widely in Asia and India for food and medicine since ancient times, ginger remains a popular spice in kitchens today. The pungent taste and aroma in curries and baked goods is actually the plant's defense against predators and pathogens. The golden, hand-shaped roots are a common sight in grocery stores, but the story of how ginger grows and reproduces is much less familiar.
The origin of this plant is lost to time, but it has been cultivated in tropical areas of the world for many centuries. Ginger was one of the first spices to reach Europe via the trade routes, and was used by ancient Romans and Greeks to aid digestion. It was grown commercially in Jamaica in the mid-1500's for export to Europe. Ginger root is used in Chinese medicine for many ailments, including headache, asthma and fever. Ginger's thick rhizomes are the source of new plants.They can remain viable for long periods, and are easily transported, which accounts for their widespread cultivation throughout the tropics.
Ginger almost never produces flowers or seeds, but reproduces almost exclusively by spreading rhizomes. The fleshy rhizome stores starches and sugars and grows away from the parent plant, horizontally beneath the soil. Buds, also called eyes, sprout from the upper surface of the rhizome and grow up through the soil to become new plants. In this way, ginger spreads out to make large patches. If the parent root dies or is cut off, the new plant can soon survive on its own. New plants are propagated for home garden and commercial use from healthy rhizomes with three to four eyes, or growing buds.
Ornamental gingers, popular in tropical landscapes, are often confused with edible ginger. Although they are unrelated, these plants are so named because of their large roots, which resemble the spice plant's rhizomes. Edible ginger grows to a height of 2 to 3 feet, and has narrow, upright green leaves. It produces rather nondescript, greenish flowers, sometimes tipped with purple, held on pine-cone-shaped spikes. Edible ginger's most distinguishing characteristic is its unmistakable, highly aromatic root.
There are many ginger cultivars, which produce roots of different sizes and slightly different levels of pungency. Japanese ginger produces a spicy rhizome with thin skin and yellow inner flesh. Commercially grown Japanese varieties include Oshoga, Kintoki and Sanshu. The more common Chinese ginger is a taller plant, which produces larger rhizomes with white colored inner flesh. Countless varieties are cultivated for local use in tropical countries.
Root nematodes frequently infect ginger growing areas. These microscopic soil insects burrow into the outer skin of the rhizome, and can easily be inadvertently transferred to a new ginger field on infected root material. For this reason, researchers have worked to develop methods of propagating nematode-free ginger, using tissue culture and other sophisticated techniques.