Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
wither [ˈwɪðər] vi (plant) вя́нуть (завя́нуть perf), со́хнуть (засо́хнуть perf)
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: