Gene flow is important in counteracting the divergence of populations but also in spreading genes among populations. Buehler et al. describe the effective mating system and contemporary gene flow in the alpine perennial Arabis alpina over a sampled landscape area of 2 km2. Paternity analysis shows that selfing predominates, while outcrossing events reveal leptkurtic pollen dispersal reaching as far as 1 km. This long-distance dispersal potential, despite the high levels of selfing, implies that beneficial alleles may reach nearby habitats and thus help facilitate adaptation of the resident populations to changing environmental conditions.