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<i>Paulownia</i> spp. are widely distributed ornamental trees with leaves abundant in secondary metabolites of high medicinal potential. Eighteen breeding clones of <i>Paulownia</i> spp. were tested in terms of their antioxidant activity and total polyphenolic contents. The 50% ethanolic extracts (2 g/30 mL) of leaves and petioles were compared in the screening step. Eight paulownia clones were selected for detailed analyses including HPTLC polyphenolic profile, verbascoside content and antibacterial activity against five bacteria species (<i>S. aureus, B. cereus, E. coli, Y. enterocolitica, S. enterica</i>). The species-specific differences in terms of antioxidant activity correlated with phenolic compounds were found mainly in the case of leaf blade extracts, the highest for <i>P. tomentosa</i> × <i>P. fortunei</i> and the lowest for <i>P. elongata × P. fortunei</i> clones. The <i>P. tomentosa</i> clones varied greatly in this regard. In the HPTLC polyphenolic profile, the occurrence of some polyphenols was proved and the specific verbascoside content was quantified (70 to 225 mg/g DW). The <i>P. tomentosa</i> × <i>P. fortunei</i> hybrids had the highest inhibitory activity, mainly against Gram-positive bacteria, whereas only slight inhibition of <i>S. aureus</i> growth was observed for <i>P. elongata</i> × <i>P. fortunei</i> clones. The obtained results indicate diverse suitability of paulownia clones as a source of active ingredients.