Water Arum
Calla palustris
Family: Araceae
What it is like
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.
Height (m): 0.3
Where it is found
Forest swamps, moorland marshes, by ponds and streams.
Europe. Naturalized in Britain.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 2
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. It is said to be very tasty. Fruit (does this include the seed?) - it should be dried and then thoroughly cooked. The dried fruit and rootstalk can be ground into an unpalatable but nutritious powder. The seed is dried, cooked and ground into a powder.
Root: includes bulbs, corms, tubers, rhizomes etc.
Seed: includes nuts, cereals, peas and beans.
Medicine
Rating: 2
Antirheumatic. Used in the treatment of colds and flu. 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. The aerial stems have been used in the treatment of sore legs.
Antirheumatic: Treats rheumatism.
Poultice: A moist, usually warm or hot, mass of plant material applied to the skin in the treatment of burns etc.
Other
Rating:
How it is grown
Requires a wet lime-free humus rich soil by water or in shallow, still or slowly flowing water in full sun. When grown on the pond margins it creeps in and out of the water. Succeeds in water up to 25cm deep.
Propagating it: Seed - best sown as soon as it is ripe in late summer in a cold frame in pots standing in about 3cm of water. Sow stored seed as early as possible in the year in a greenhouse. The germination rate of stored seed is often poor. When large enough to handle, prick the seedlings out into individual pots and grow them on in trays of water in the greenhouse for at least their first winter, planting them out into their permanent positions in late spring or early summer, after the last expected frosts. Division in spring. Very easy, it is possible to divide this plant at almost any time in the growing season. Any part of the stem, if placed in water or a pot of very wet soil, will quickly root away to form a new plant. Stem cuttings in summer, rooted in wet mud.
Best place to grow: Pond; Bog Garden;
Habit: Perennial
Hardiness: 4-8
Growth:
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Wet, water
Things to keep in mind
The plant contains calcium oxylate crystals. 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.