Allium tuberosum

Allium tuberosum (garlic chives, Oriental garlic, Asian chives, Chinese chives, Chinese leek) is a species of onion native to southwestern parts of the Chinese province of Shanxi, and cultivated and naturalized elsewhere in Asia and around the world. Allium tuberosum is a rhizomatous, clump-forming perennial plant growing from a small, elongated bulb (about 10 mm, 13⁄32 inch, across) that is tough and fibrous. Unlike either onion or garlic, it has strap-shaped leaves with triangular bases, about 1.5 to 8 mm (1⁄16 to 5⁄16 in) wide. It produces many white flowers in a round cluster (umbel) on stalks 25 to 60 cm (10 to 24 in) tall. It grows in slowly expanding perennial clumps, but also readily sprouts from seed. In warmer areas (USDA zone 8 and warmer), garlic chives may remain green all year round. In cold areas (USDA zones 7 to 4b), leaves and stalks completely die back to the ground, and resprout from roots or rhizomes in the spring. The flavor is more like garlic than chives. Originally described by Johan Peter Rottler, the species name was validly published by Curt Polycarp Joachim Sprengel in 1825. A. tuberosum is classified within Allium in subgenus Butomissa (Salisb.) N. Friesen, section Butomissa (Salisb.) Kamelin, a group consisting of only A. tuberosum and A. ramosum L., which have been variously regarded as either one or two genetic entities. A. tuberosum originated in the Siberian–Mongolian–North Chinese steppes, but is widely cultivated and naturalised, 'It has been reported as growing wild in scattered locations in the United States (Illinois, Michigan, Ohio, Nebraska, Alabama, Iowa, Arkansas, and Wisconsin). However, it is believed to be more widespread in North America because of the availability of seeds and seedlings of this species as an exotic herb and because of its high aggressiveness. This species is also widespread across much of mainland Europe and invasive in other areas of the world. A late summer- to autumn-blooming plant, A. tuberosum is one of several Allium species known as wild onion and/or wild garlic that, in various parts of the world, such as Australia, are listed as noxious weeds or as invasive 'serious high impact environmental and/or agricultural weeds that spread rapidly and often create monocultures'. Often grown as an ornamental plant in gardens, several cultivars are available. A. tuberosum is distinctive by blooming later than most native or naturalised species of Allium. It is cold-hardy to USDA zones 4–10 (−30 to +35 °F, −34 to 2 °C). Garlic chives are regarded as easy to grow in many conditions and may spread readily by seeds or can be intentionally propagated by dividing their clumps. A number of varieties have been developed for either improved leaf (e.g. 'Shiva') or flower stem (e.g. 'Nien Hua') production. While the emphasis in Asia has been primarily culinary, in North America, the interest has been more as an ornamental. 'Monstrosum' is a giant ornamental cultivar.