The species lays up to 2,000 eggs on the host plant during the early fall. They lay their eggs on the undersides of leaves of new fall basal growth on its host plant, St. John's Wort. The larvae feed for a month on the leaves, emerging at night and hiding during the day. When full grown they move to the soil to pupate. After two weeks they emerge as adults. In the spring the adults feed upon new growth of their host plant.
Chrysolina hyperici is most often known in English by the common names "St. Johnswort Beetle", "Saint John's Wort Beetle" or close variations. In the United StatesC. hyperici is also known by the common name "klamathweed beetle" from one of the common names of Hypericum perforatum.