Catalyzes the glycosylation of flavonoids from UDP-glucose. Uses a wide range of flavonoid substrates including flavonols (quercetin, kaempferol, isorhamnetin, 3-OH 7,2',4'-MeO-flavone), flavones (luteolin, apigenin), flavanones (naringenin, hesperetin), flavanonols (taxifolin), isoflavones (genistein, daidzein), flavonol glycosides (quercitrin, isoquercitrin, rutin), and chalcones (isoliquiritigenin). Specific for the C-7 position, with a 20-fold lower activity for the C-3 position.