Jargeau vetch is a weed found along roadsides and fences. It is difficult to control in no-till crops, perennial fruit crops, and meadows and pastures. It is particularly troublesome and difficult to suppress in conventional soybeans. This plant is indifferent to soil type but is frequently associated with light soils. It is drought-tolerant and grows from full sun to partial shade.
Its stem is slender and highly branched. It has a prostrate to climbing habit and can reach 2 m in length. The plant clings to neighboring plants using tendrils or intertwines with its own stems to form a cushion-like mass. The alternate, sessile leaves of Jargeau vetch are composed of 6 to 12 pairs of opposite leaflets and terminate in a sparsely branched tendril. The leaves are 4 to 10 cm long, and the leaflets are 1 to 3 cm long. They are linear, tapering to a point, and have short petioles and are finely pubescent.
The flowers are grouped in dense clusters on peduncles 3 to 6 cm long. Ten to thirty flowers are arranged along one side of the inflorescence. They are blue, mauve, or purple and measure 8 to 13 mm.
The fruits are flattened pods, light brown to black in color. They are 2 to 5 cm long and contain 5 to 8 seeds. The seeds are spherical to rounded, 2.5 to 3.5 mm in diameter, and reddish-brown, sometimes slightly speckled.
Source: IRIIS phytoprotection - Technical sheet, Tufted vetch
