In the present study, three indigenous species of Solidago genus (Solidago gigantea, Solidago virgaurea and Solidago canadensis) have been analyzed for the assessment of polyphenolic, phenyl propane derivates and essential oil contents. In addition, a comparative morphological study was also described. The leaves and the flowers of the three Solidago species were studied by scanning electron microscopy (SEM). The qualitative and quantitative characterizations of the main polyphenolic compounds from the hydrolyzed extracts were carried out by using high performance liquid chromatography with UV detection (HPLC-UV), high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) and gas chromatography coupled with mass spectrometry (GC-MS) for the essential oil determination. The dominant flavonoidic aglycone found for all three species was quercetol with its highest concentration registered in Solidago canadensis. Four components, α-pinene, mircene, bornyl acetate and germacrene D, were detected in all the analyzed samples of essential oils. According to the comparative morphological analysis, morphoanatomical differences were observed for the tryhomes, stomata and flowers of the studied Romanian Solidago species.