Plantago lanceolata is considered an obligate outcrosser, a trait which is maintained by both protogyny and S-RNase driven self-incompatibility system. Reproduction occurs via seeds that germinate in the following summer or remain in the soil seedbank, and clonally by producing side-rosettes. In the Åland Islands P. lanceolata occurs mainly on dry meadows and its spatial population structure has been closely recorded for the past decade. It is the main host plant of the Glanville fritillary butterfly (Melitaea cinxia) and the only host of the powdery mildew, Podosphaera plantaginis.