Aims It has been assumed that plants grown from persistent soil seed bank (PSSB) are not less competitive because of soil storage. Our objective was to determine whether the competitiveness of plants of PSSB will decrease. Methods We compared heights and biomass of Eupatorium adenophorum plants grown from fresh seeds and grown from one-year-old buried PSSB seeds with no competition (control) and competition with density of 0.25, 1, 4 and 8 plants·cm–2. We also compared plants grown from fresh seeds and three-year-old buried PSSB seeds with no competition (control) and competition with density of 0.10, 0.17, 0.60 and 2.17 plants·cm–2. The PSSB seeds and fresh seeds were germinated simultaneously, and seedlings were grown in garden pots up to 175 days. Plant height was measured every 15 days and biomass was measured every 30 days (3 replicates). Important findings The height and biomass of plants of one- and three-year-old buried PSSB seeds were lower than for plants germinated from fresh seeds in the control (no competition) and with competition at most measuring times. However, most differences were not statistically significant.