This vine is centered in the central and lower Mississippi watershed, and it appears to be native along major rivers in western regions of Ky., at least the Ohio Rv. downstream of Louisville, the Green Rv., Cumberland Rv., Tennessee Rv. and their major tributaries. W. macrostachya became cultivated in Ky. early after Virginian settlement (as "Kentucky Wisteria"), especially around Louisville and elsewhere in northern counties. Short (1840) listed it as frutescens: "A flowering pea-vine, now common in gardens and shrubberies; abundant on the banks of Little River in the West of Kentucky." Open dots on the map indicate possible adventive status, or in some cases represent unverified historical data of Gm. The exact original range remains uncertain.