Calamus, Sweet flag
Acorus calamus

Family: Acoraceae

What it is like

A shrub or small tree. It grows 5 m tall. There are prickles along the stem. The leaves are twice divided and there are 8-18 pairs of pinnae. There are up to 50 pairs of pinnules on each pinnae. The flowers are yellow. They are in large clusters at the ends of branches. The pods are flattened.

1% volatile oil; a bitter glucoside - acorin; There is only one genus in the Acoraceae. There are 2-4 Acorus species. It has a long history of use for perfume and medicine.

Where it is found

Its natural range is the warm temperate regions of Iran and India. They are found throughout the Philippines both cultivated and wild, growing in swamps. In Papua New Guinea it grows from sea level to 2600 m altitude. It can tolerate frost but cannot tolerate drought. It normally occurs in ditches, swamps, and on the edges of lakes and streams. It grows in wetland. It grows best in water no deeper than 22 cm. Often the plant grows in dense pure stands. It is mostly in places with a temperature below 20°C. It suits hardiness zones 3-10.

Countries/locations it is found in

Afghanistan, Armenia, Asia, Australia, Austria, Balkans, Bangladesh, Belarus, Bhutan, Bosnia, Brazil, Britain, Canada, Caucasus, China, Czech Republic, Denmark, Egypt, Estonia, Europe, France, Germany, Himalayas, Hungary, India, Indochina, Indonesia, Iran, Ireland, Italy, Japan, Korea, Laos, Latvia, Lithuania, Luxembourg, Macedonia, Malaysia, Maldives, Mediterranean, Middle East, Mongolia, Myanmar, Nepal, Netherlands, New Zealand, North Africa, North America, Northeastern India, Pacific, Pakistan, Papua New Guinea, Philippines, Philippines, Poland, Russia, Scandinavia, SE Asia, Serbia, Siberia, Sikkim, Slovenia, South America, Spain, Sri Lanka, Sweden, Thailand, Turkey, Türkiye, Ukraine, USA, Vietnam, Yugoslavia

How it is used for food

The underground stems are ground and used to flavour food. They can be eaten raw. They have a gingery peppery taste. It should probably only be eaten sparingly with caution. They contain a bitter glucoside called acorin. The forms of Acorus in Asia contain a chemical called asarone which causes cancer. The centre of the above ground section can be eaten. The underground stem can be washed, peeled, chopped into 1 cm long pieces and cooked for 20 minutes with several changes of water then simmered for 20 minutes in sugar syrup to produce candy.

It is sold in local markets. It is not known if it is used for food in Papua New Guinea.

Edible parts

Roots, rhizome, leaves, stems, herb, spice

How it is grown

It can be grown by dividing the rootstock. These are planted 6 cm deep and spaced 30 cm apart. It can also be grown by seeds.

Tender young stalks are harvested. The young underground stem needs to be separated from the roots and pulled or dug out.

Its other names

Local names

Airi, Ajer, Ajeras, Aleras, Ayer, Bach, Baghshtak, Baje gida, Bas, Boch, Bojho, Bos, Changpu, Flagroot, Fortunate bullrush, Huvagoh, Jagier, Jaringao, Jeringau, Kalmos, Kalmus, Khnkegheg, Lepiech, Lin-lay, Lin-ne, Lubigan, Myrtle flag, Pravi kolmež, Puskvorec obecny, Sweet cane, Sweet sedge, Tatarak. Vacha, Vasa, Vasambu, Vavambu, Vayambu, Vekhand, Wan nam

Synonyms

Acorus asiaticus Nakai; Acorus terrestris Spreng.; and others