Vicia cracca is a perennial herbaceous vine, colonial from spreading rhizomes, climbing or trailing to 2 m, often forming mats, stems striate-angular, finely hairy.
Leaves alternate, evenly pinnate, terminal leaflet modified into a simple or branched tendril, leaflets 5-10 pairs, linear to oblong, to 3 cm long, tips abruptly pointed, lateral veins at narrow angle to midrib, stipules lance to semi-arrow shaped, small.
Flowers blue-violet, pea-flower shaped, to 1.3 cm, calyx ca 0.2 cm, lobes unequal, in dense, one-sided racemes with long stalk, opposite leaves, flowers produce nectar to attract pollinators for outcrossing, pollinated by bees, including Apis mellifera, Bombus vagans, B. fervidus, B. ternarius, Zygaena sp. and butterflies. The “honey robber”, Bombus terricola, bites holes in the base of the flower to get at nectar without transferring pollen However, anthers shed pollen before flowers open, producing self-pollination (Mulligan and Kevan 1973; Aarssen et al. 1986); blooms June-Aug.
Fruit pods lance-linear, smooth, 2.5 cm long, 0.6 cm wide, splitting and twisting open; fruits Aug. Sept., Seeds eaten by some birds and rodents (Martin et al 1951).
Wetland status: UPL.
Frequency in NYC: Infrequent.
Habitat: Open fields, roadsides. Soil Ph 4.9-7 (USDA, NRCS 2010).
Notes: Poisonous (Aarssen et al. 1986). Roots attacked by the nematodes Meloidogyne arenaria and M. hapla. Attacked by the moth Lygephila pastinum. Infected by the fungi Ascochyta nigripycnidicola (Deuteromycotina) and Uromyces verrucosae-craccae (Basidiomycotina), and by the Alsike clover mosaic virus (Aarssen et al. 1986, Agrios 1988).