Summary: The dumping of garden waste is thought to contribute to the spread of environmental weeds, but it is difficult to collect suitable data to confirm or refute this hypothesis. A qualitative model was developed that combined three plant attributes: local growth rate, mean dispersal distance and dispersal curve. This model was used to test the effect of garden waste dumping on the spread of weeds with different characteristics. We found that garden dumping can greatly enhance the spread of weed species with limited natural dispersal. For those weeds that already disperse long distances, by wind or birds, garden dumping makes little difference to the time taken to reach a reserve. The modelling also underlined the difficulty of eliminating infestations of weeds that are wind or bird-dispersed.