Everlasting Pea (Lathyrus latifolius)
Everlasting Pea is a vigorous vine that can take over whole hillsides. It compensates us for the space it takes with a glorious array of flowers in shades from white through deep magenta, often (as here) with stripes or bicolor patterns.
Gray describes the genus and the species:
Style dilated and flattish (not grooved) above, hairy along the inner side (next the free stamen). Sheath of the filaments scarcely oblique at the apex. Otherwise nearly as in Vicia. Our species perennial and mostly smooth plants. (Lathyros, a leguminous plant of Theophrastus.)
L. latifolius L. (EVERLASTING or PERENNIAL PEA.) Tall perennial with broadly winged stems; leaves and stipules coriaceous and veiny; petioles mostly winged; the 2 elliptic to lanceolate leaflets 0.5-1 dm. long; peduncles stiff, many-flowered; flowers showy, pink, purple, or white. Frequently cultivated, and escaping to roadsides and thickets, Ct. to 1). C. (Introd. from Eu.)