According to the folk calendar - Maria Yagodnitsa

This date is named after St Mary Magdalene, whose memory is revered by the Orthodox Church on this day On Mary’s day, an abundance of berries ripened in the forests, which is why the people called Mary the Berry Girl Women and children went to their gathering, and returned back with full baskets of currants, raspberries, strawberries, blueberries, blueberries