What defines a biennial weed's life cycle?

A biennial weed is specifically characterized by its two-year life cycle. In the first year, the plant typically germinates, grows vegetatively, and stores energy as rosettes or leaves, establishing a root system. During the second year, it flowers, produces seeds, and then dies. This two-year cycle distinguishes biennial weeds from annuals, which complete their life cycle in one year, and perennials, which last for multiple years and often have persistent root systems or structures to survive unfavorable conditions. The defining feature of biennial weeds is their requirement to span two growing seasons to complete reproductive maturity, making “having a two-year life cycle” the correct definition.