Habitat fragmentation has been so severe these last decades and plant populations have become so small and isolated that ecological restoration of biotopes may not allow viable populations of many strongly declining plant species to recover without additional human intervention. Indeed, the restored populations, despite an increase in census population size, and so an apparent success of the restoration plans, may not be viable on the long term due to genetic erosion restricting the evolutionary potential of the populations and inbreeding depression reducing plant fitness. When connectivity by gene flow between populations cannot be restored and in the absence of a persistent seed bank in the soil, genetic restoration and/or rescue have to be considered through plant translocations. Evaluating the genetic status of the potential seed source and target populations is essential for appropriately designing plant translocation protocols, and genetic monitoring of the restored populations is needed for assessing the recovery success. Here we illustrate how genetics tools, using nuclear and plastid DNA markers and fitness-related phenotypic characters, have been used for designing the translocation protocol and for monitoring reinforced and reintroduced populations of the self-incompatible, clonally-propagating, threatened Arnica montana in southern Belgium (realised in the framework of the EU-LIFE project “Herbages” -LIFE11 NAT/BE/001060). Given that most small populations showed a very small number of genets, and consequently restricted compatible mate availability, as well as inbreeding depression at early development stages, and given the moderate levels of genetic differentiation between most populations, we used mixed material from the two last large Belgian populations as seed source for plant translocation. Monitoring of the translocated populations has consisted of estimating plant fitness and genetic diversity of the transplants, of the seeds produced by the transplants, and of the newly established recruits, as well as inferring gene dispersal and the risk of outbreeding depression.