Common Name: Sweet Violet

General Information

Viola odorata is a stemless, evergreen perennial plant forming a dense mat of growth around 3 - 15cm tall[].
The plant is harvested from the wild for local use as a food and medicine. It is cultivated for its essential oil, especially in southern France[], and is often grown as an ornamental, where it is valued particularly for its scented flowers in winter and can be used as a ground cover.

Known Hazards

All members of this genus have more or less edible leaves and flower buds, though those species with yellow flowers can cause diarrhoea if eaten in large quantities[, , ]. The flowers of this species can be blue, purple or white.

Botanical References

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Range

Europe - Norway to Portugal, east to Ukraine, Bulgaria and Greece; W. Asia - Turkey Lebanon, Iraq, Iran; N. Africa - Macaronesia, Morocco to Tunisia

Habitat

Fields, hedgerows and woodlands, especially on calcareous soils[, , ].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Perennial
Height	0.10 m
Pollinators	Bees, Cleistogamous
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Viola odorata is hardy to about -20°c[].
Succeeds in most soils but prefers a cool moist well-drained humus-rich soil in partial or dappled shade and protection from scorching winds[, , , ]. When grown in the open it prefers a moderately heavy rich soil[]. Plants have done very well in a hot dry sunny position on our Cornish trial grounds[]. Tolerates sandstone and limestone soils.
Sweet violets are very ornamental plants, there are many named varieties[]. They produce their delicately scented flowers in late winter and early spring - these are designed for fertilisation by bees and since there are few bees around at this time of year these flowers seldom set seed[]. However, the plants also produce a second type of flower later in the year. Known as cleistogamous, these never open, but seed is produced within them by self-fertilization[]. The plants will often self-sow freely when well-sited[]. They can also spread fairly rapidly at the roots when they are growing well[].
Responds well to an annual replanting in rich loose leafy soils[].
All members of this genus have more or less edible leaves and flower buds, though those species with yellow flowers can cause diarrhoea if eaten in large quantities[, , ].

Edible Uses

Young leaves and flower buds - raw or cooked[, , ]. Usually available all through the winter[]. The leaves have a very mild flavour, though they soon become quite tough as they grow older. They make a very good salad, their mild flavour enabling them to be used in bulk whilst other stronger-tasting leaves can then be added to give more flavour[]. When added to soup they thicken it in much the same way as okra[, , ]. Also used as a flavouring in puddings etc.

A tea can be made from the leaves[].

Flowers - raw. Used to decorate salads and desserts[, , ]. A sweet mild flavour with a delicate perfume, the flowers are an especially welcome decoration for the salad bowl since they are available in late winter[]. The flowers are also used fresh to flavour and colour confectionery[].

A soothing tea can be made from the leaves and flowers[, ].

A leaf extract is used to flavour sweets, baked goods and ice cream[].

Medicinal

Sweet violet has a long and proven history of folk use, especially in the treatment of cancer and whooping cough[, , ]. It also contains salicylic acid, which is used to make aspirin[]. It is therefore effective in the treatment of headaches, migraine and insomnia[].

The whole plant is anti-inflammatory, diaphoretic, diuretic, emollient, expectorant, and laxative[, , , , ]. It is taken internally in the treatment of bronchitis, respiratory catarrh, coughs, asthma, and cancer of the breast, lungs or digestive tract[, ].
Applied externally, the plant is used to treat mouth and throat infections[].
The plant can either be used fresh, or harvested when it comes into flower and then be dried for later use[].

The flowers are demulcent and emollient[]. They are used in the treatment of biliousness and lung troubles[]. The petals are made into a syrup and used in the treatment of infantile disorders[].
A distillation of the flowers is an effective treatment against flu and the common cold[].
The flowers (especially of var. maxima) are a source of rutoside. They also contain anthocyanins, violanin chloride, which on hydrolysis yields glucose, delphinidin, rhamnose and p-coumaric acid. A high content of tocopherol is also reported from flowers[].

The roots are a much stronger expectorant than other parts of the plant but they also contain the alkaloid violine which at higher doses is strongly emetic and purgative[, , ]. They are gathered in the autumn and dried for later use[].

The seeds are diuretic and purgative. They have been used in the treatment of urinary complaints are considered to be a good remedy for gravel[].

A homeopathic remedy is made from the whole fresh plant[]. It is considered useful in the treatment of spasmodic coughs and rheumatism of the wrist[]. It has a specific action on the ear and is also used in treating rheumatism in the upper parts of the body , worm affections in children, pain due to uterine fibroids, snake-bites, bee-stings[].

An essential oil from the flowers is used in aromatherapy in the treatment of bronchial complaints, exhaustion and skin complaints[].

Agroforestry Uses:

Plants can be grown as a ground cover when spaced about 30cm apart each way[]. They make an effective weed-excluding cover[].

Other Uses

An essential oil from the flowers and leaves is used in perfumery[, ]. 1000kg of leaves produces about 300 - 400g absolute[].

The flowers are used to flavour breath fresheners[].

A pigment extracted from the flowers is used as a litmus to test for acids and alkalines[, , , ].

Propagation

Seed - best sown in the autumn in a cold frame. The seed requires a period of cold stratification and the germination of stored seed can be erratic. Prick out the seedlings into individual pots when they are large enough to handle and plant them out in the summer.
Division in the autumn or just after flowering. Larger divisions can be planted out direct into their permanent positions, though we have found that it is best to pot up smaller divisions and grow them on in light shade in a greenhouse or cold frame until they are growing away well. Plant them out in the summer or the following spring.