Quality and yield in St. John's wort (Hypericum perforatum L.) harvested in different phenological stages

Two experiments were conducted in the province of Ñuble, Chile during the 1997/98 and 1998/99 seasons with the objective of evaluating the effect of harvesting date on the yield and quality of St. John's wort ( Hypericum perforatum L.) in the second year of production. The apical 25 cm of the stem were harvested in the following stages: flower bud, beginning of flowering, full flower and petal drop. A randomized complete block design with four replications was used. The best yield (fresh, dry and threshing weight) and the highest hypericin content were obtained at the petal drop stage. Nevertheless, the results indicate that the best time to harvest St. John's wort is when 10 to 20% of the flowers are open and the rest are in the bud stage.