Tufted vetch (Vicia cracca, L. 1753)

Identity

Tufted vetch (Vicia cracca L., 1753), also called cow vetch, bird vetch, blue vetch or boreal vetch, is a perennial herbaceous climber in the genus Vicia, family Fabaceae. Plants of the World Online accepts the name published by Linnaeus in 1753. ^{1 6}

The genus name Vicia comes from Latin vincio, “I bind myself,” describing the plant's tendril-climbing behavior. The epithet cracca is less certain: through the botanist Rivinus and Pliny, it may derive from an ancient Greek name for a plant resembling a vetchling. No source resolves the origin definitively. ³

Recognition

Angular climbing stems without dense hairs attach to surrounding vegetation through branched tendrils at the leaf tips. Depending on conditions, Vicia cracca commonly reaches 30 cm to 2 m (1 to 6.5 ft) in length. ^{4 3}

Pinnate leaves have 5 to 15 pairs of narrow leaflets, with the final pair modified into a tendril. The most reliable feature is a dense, one-sided spike of 10 to 30 blue-violet flowers, each 8 to 13 mm (0.3 to 0.5 in) long, much fuller than in sparsely flowering vetches. ^{4 2}

Self-incompatible flowers produce no seed without a visit from a bumblebee or another bee. Seed reproduction therefore depends entirely on pollinators. The resulting flattened brown pods, 2 to 2.5 cm (0.8 to 1 in) long, release 3 to 6 red-brown seeds by bursting open explosively when ripe. ⁴

Useful taxonomy

For Tufted vetch, Plants of the World Online accepts Vicia cracca L., published in 1753. Numerous regional varieties and subspecies appear in its synonymy, including Vicia cracca subsp. gerardi Gaudin and Vicia cracca var. grandiflora Lange ex Willk., without displacing the accepted name. ¹

Within Fabaceae, the species belongs to subfamily Faboideae, the legumes with pea-shaped flowers and splitting pods. Cultivated Vicia, including field bean and common vetch, belong to the same group. ¹

Hedge vetch, Vicia sepium, is the likeliest field confusion. It has only 2 to 6 grouped flowers, shorter than the leaf from whose axil they emerge, compared with the long, dense spike of Vicia cracca. ⁴

Habitat and range

Temperate Eurasia supports the native populations of Vicia cracca, from Europe and Scandinavia to Siberia and Japan. It occupies meadows, hedges, banks and woodland edges on moist to well-drained ground. ^{3 1}

French records in INPN list this native species under vesce cracca. It is widespread across metropolitan France. ⁶

Early introduction as a North American forage crop was followed by invasion in several regions, from southern Canada to northern South Carolina. In Alaska, Vicia cracca enters undisturbed habitats and climbs into the lower branches of trees and shrubs, an unusual behavior for a weed. Seeds remain viable in Alaskan soil for about five years. Resistance to both fire and drought helps explain its rapid return after fire or clearing. ^{5 7}

Life cycle and reproduction

Creeping roots and seed both reproduce Vicia cracca. The spreading root network bears nitrogen-fixing nodules and extends the colony independently of seed production. ⁵

In its northern temperate range, flowering runs from May to August. Each self-incompatible flower requires a bumblebee or another bee to form a pod. Pods ripen from July to September, scattering seeds through explosive splitting. This short-distance dispersal partly explains why patches remain concentrated initially, before the root network extends them. ^{4 2}

Brief summer drought and harsh winters are both tolerated. Aboveground foliage dies with the first hard frosts, but deep roots and seeds in the soil survive the unfavorable season. ^{5 2}

Uses and risks

Forage production is the main use: Vicia cracca is grown and harvested as a pasture legume relished by livestock. Root nodules add nitrogen to the soil, benefiting neighboring grasses. It also provides a regular nectar source, visited by bumblebees throughout summer. ^{3 2}

Boiled or roasted seeds were eaten during famine, and young leaves sometimes served as a tea substitute. No toxicity is documented for humans or the main domestic animals, although tolerance in horses remains poorly documented. ³

Agricultural problems arise mainly beyond its native range. In North America, it reduces forage yields by twining around crops and colonizes roads, power-line corridors and woodland edges. Established infestations require several years of sustained management. ^{5 7}

Varieties, look-alikes and related plants

Horticulture recognizes no cultivar of Vicia cracca: it is a wild plant never selected for ornament, unlike agricultural vetches such as Vicia sativa. ³

Likely look-alikes include the following plants:

• Vicia sepium, with short spikes of 2 to 6 grouped flowers, shorter than the leaf;
• Vicia sylvatica, with white flowers veined violet rather than uniformly blue-violet;
• some Lathyrus species with branched tendrils, often with broader leaflets.

Counting flowers in each spike remains decisive. More than ten blue-violet flowers, 8 to 13 mm (0.3 to 0.5 in) long, in a dense one-sided spike fits Vicia cracca. A group of only 2 to 6 flowers shorter than the adjacent leaf points to Vicia sepium.

Main sources

• Plants of the World Online / Kew, Vicia cracca L.
• Royal Horticultural Society, Vicia cracca - common tufted vetch
• Plants For A Future, Vicia cracca
• Botanical Society of Britain and Ireland, Vicia cracca - Tufted Vetch
• University of Alaska Fairbanks Cooperative Extension, Invasive Plant Issues - Bird Vetch
• INPN / MNHN, Vicia cracca L., 1753 - Vesce cracca
• Go Botany / Native Plant Trust, Vicia cracca - Bird vetch
• PlantaLearn, Vesce cracca (Vicia cracca)