Raw data from: Quantitative distribution of flavan-3-ols, flavonols, flavanone and salicylic acid in five varieties of winter dormant Salix spp. by LC-MS/MS

• Winter dormant willow contains polyphenolic compounds of valuable interest. • High concentrations of catechin, naringenin and salicylic acid. • High variations in individual flavonoids were observed. • Constantly low concentrations of all measured polyphenolic compounds in wood subparts. • All five varieties contained high TPC in buds and bark, highest in bark of S. dasyclados x viminalis (6.7%).