Common licorice Glycyrrhiza glabra

Licorice is a flowering, herbaceous perennial legume native to Europe and parts of Asia. Its roots produce an intensely sweet compound used in teas and candies. Its genus name is derived from the Greek for "sweet root" and it has been used for centuries as a source of glycerin, a sweetener and a component in folk medicines. Plants with similar flavoring but not botanically related are anise, fennel, and star anise. The sweet compound is glycyrrhizin and is 50 to 170 times sweeter than sugar (sucrose). The extract has antiviral, anti-inflammatory, antioxidant, antimicrobial, and antimutagenic properties. The earliest record of use of this plant medicinally is 2100 BC. Consumption in high doses is toxic. Licorice extracts are treated to remove the majority of glycyrrizin, the problematic ingredient, prior to use in products, leaving enough to maintain flavor but decreasing toxicity.

Licorice requires deep well-cultivated fertile moisture-retentive soil for good root production and prefers a sandy soil with abundant moisture. It does not flourish in clay. Slightly alkaline conditions produce the best plants. It can tolerate high winds, but not salty coastal winds or clay soils. Plant growth is initially slow, but once established the species can become weedy and difficult to remove if not kept under control by regular harvesting.

Diseases, Insects, and Other Plant Problems: spider mites, slugs, snails, powdery mildew, and rust.