Prickly Lettuce

Lactuca serriola

Physical Characteristics

Lactuca serriola is a BIENNIAL growing to 1.5 m (5ft) by 0.3 m (1ft in). See above for USDA hardiness. It is hardy to UK zone 7. It is in flower from July to September, and the seeds ripen from August to September. The species is hermaphrodite (has both male and female organs). The plant is self-fertile. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Distribution

S. and C. Europe, incl Britain, from the Netherlands south and east to N. Africa and the Himalayas.

Habitats

Cultivated Beds; East Wall. In. South Wall. In. West Wall. In.

Edible Uses

Edible Parts: Leaves Oil Oil Shoots Edible Uses: Oil Oil Young leaves - raw or cooked[13, 55, 62]. A bitter flavour[85]. The young tender leaves are mild and make an excellent salad[183, 217], but the whole plant becomes bitter as it gets older, especially when coming into flower[K]. As a potherb it needs very little cooking[183]. Large quantities can cause digestive upsets[62]. Young shoots - cooked. Used as an asparagus substitute[13]. An edible oil is obtained from the seed[46, 61, 105]. The oil must be refined before it is edible[114]. A pleasant flavour[114, 183].

Medicinal Uses

Anodyne Antipyretic Diuretic Homeopathy Hypnotic Narcotic Sedative Urinary The whole plant is rich in a milky sap that flows freely from any wounds. This hardens and dries when in contact with the air. The sap contains 'lactucarium', which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets, nor is it addictive. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower. It is collected commercially by cutting the heads of the plants and scraping the juice into china vessels several times a day until the plant is exhausted. This species does not contain as much lactucarium as L. virosa. An infusion of the fresh or dried flowering plant can also be used. The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness whilst excess causes restlessness and overdoses can cause death through cardiac paralysis. The fixed oil from the seeds is said to possess antipyretic and hypnotic properties. A homeopathic remedy is made from the plant. It is used in the treatment of chronic catarrh, coughs, swollen liver, flatulence and ailments of the urinary tract.

Known Hazards

The mature plant is mildly toxic[13].