Bitter Vetch: a Wildflower

Bitter vetch (Lathyrus montanus) is a distant relative of the sweet pea that has been used as a food plant.

Bitter vetch grows in woods, thickets and hedgerows in scattered locations, particularly in west and north Britain.

The second part of the botanical name, montanus, is derived from the Latin for mountain, but although it is common in hilly areas it is not exclusively an upland plant and can be found at sea level in the West Country.

Bitter vetch is a short, erect, delicate plant, growing to between 6 and 16 inches high (15-40 cm). The leaves comprise two to four pairs of leaflets and end in a short point. The stem is hairless and has two wings.

There are tubers at the base that store food.

The plant spreads by extending stems that creep along the ground.

Bitter vetch is a perennial, living for many years and dying back each winter to the rootstock with its string of small, roundish tubers.

Bitter vetch flowers from April to July.

The flower spikes have two to six veined flowers that are crimson at first, then fading to blue or green.

The flowers are pollinated by bees. Brushlike hairs below the stigma collect the pollen from the anthers. When a bee feeds on nectar at the base of the flower, this brush dusts the underside of the insect with pollen. At the same time, any pollen collected from a previously visited flower will be transferred to the stigma.

When the flowers die back, smooth pods are formed that contain up to six seeds. The pods are 1.25-2 inches long (3-5 cm).

Bitter vetch has been used as a vegetable since the Middle Ages. In northern Scotland and the Western Isles it was grown in the past as a subsistence crop, the tubers being eaten or used to flavour whisky. The tubers, when eaten raw, have been said to taste like chestnuts.

Bitter vetch tubers were preserved by being tied in bundles and hung under the thatch of a croft or cottage.