This arborescent willow is abundantly naturalized in some northeastern regions, but it remains much less common in southeastern states (K). The earliest records in Ky. were by Pr (1893), Nelson (1919), Slack (1941) and B (1942). It is not clear if some records are from truly naturalized plants, but trees of this species or its hybrids do seem to be spreading slowly along major rivers. There are several cultivars, including the popular form with yellow twigs known as cv. Vitellina or var. vitellina (L.) Stokes (FNA 7). Several Ky. colls. have been determined as hybrids with fragilis (X rubens Schrank) by Argus (1986): from DAVI, HEND, FAYE, FRAN and MADI. A few colls. from FAYE, HENR (KY) and elsewhere (CW) appear to be hybrids with babylonica (X sepulcralis Simonkai); see also notes under pentandra (as X ehrhatiana). However, these Eurasian species of section Salix are mostly polyploids (with 2n = 76), and do not hybridize with the natives in Ky. (2n = 38). S. alba was a major initial source of salicin, the glycoside used to synthesize acetyl-salicylic acid (or "aspirin") by the Bayer company. However, most or perhaps all species of Salix are reported to have similar chemistry. Raw bark extract had much traditional use, and included more diverse chemistry with less pronounced side effects than pure aspirin (Shara & Stohs 2015).