Non-native plants are often seen as peripheral to trophic networks due to a lack of co-evolution with local biota, but the factors shaping their integration remain poorly understood. Using a continent-wide dataset of 127,000 plant–microherbivore interactions across Europe, we show that native plants host more microherbivore species than non-natives. Among non-native plants, the number of associated microherbivore species was better predicted by time since introduction and range size in the introduced range than by relatedness to native flora or geographic origin. Species introduced more than two centuries ago, or with ranges as large as the average native plant, supported similar numbers of microherbivores as natives, though with a greater share of generalists. Our findings suggest that trophic networks can absorb novelty rapidly, with non-natives attaining levels of microherbivory richness comparable to natives over relatively short timescales, but the persistence of specialised interactions remains dependent on native flora.