This occasionally cultivated tetraploid (2n = 36) perennial is locally escaped in northeastern regions, but virtually absent elsewhere in North America (FNA 4, PL). The only record from Ky. is a coll. in DAVI (MUR): Austin & Gentry #3495, 3 Aug 1966, waste pond bank by oil storage tank, 1.2 m W of US 431 on Marksburg Rd., ditch crossing road.