Water Arum

Calla palustris

Physical Characteristics

Calla palustris is a PERENNIAL growing to 0.3 m (1ft) by 0.3 m (1ft in). See above for USDA hardiness. It is hardy to UK zone 4. It is in flower from June to July, and the seeds ripen from August to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Flies. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid and neutral soils and can grow in very acid soils. It cannot grow in the shade. It prefers wet soil and can grow in water.

Distribution

Europe. Naturalized in Britain[17].

Habitats

Pond; Bog Garden;

Edible Uses

Edible Parts: Fruit Root Seed Edible Uses: Rhizome - cooked. It is usually prepared by drying the root, grinding it into a powder and then thoroughly cooking it to ensure that any acrimonious principle is completely destroyed. The resulting powder is rich in starch and can be used as a flour for making bread etc, especially in conjunction with cereal flours[1, 2, 55, 100, 183]. It is said to be very tasty[65]. Fruit (does this include the seed?) - it should be dried and then thoroughly cooked[172]. The dried fruit and rootstalk can be ground into an unpalatable but nutritious powder[172]. The seed is dried, cooked and ground into a powder[207].

Medicinal Uses

Antirheumatic Poultice Antirheumatic. Used in the treatment of colds and flu[172]. A tea made from the dried root has been used in the treatment of flu, shortness of breath, bleeding and as a poultice on swellings and snakebites[222, 257]. The aerial stems have been used in the treatment of sore legs[257].

Known Hazards

The plant contains calcium oxylate crystals[222]. These cause an extremely unpleasant sensation similar to needles being stuck into the mouth and tongue if they are eaten, but they are easily neutralized by thoroughly drying or cooking the plant or by steeping it in water[65].