Established weeds continue to spread, and new weeds continue to establish on both state and national scales. A list of the total pool of alien plant taxa occurring in NSW is a baseline resource that can help predict which taxa might emerge as new weeds, and which established weeds might expand their ranges in future. However, the number and identity of all naturalised and pre-naturalised plant taxa currently occurring in NSW is uncertain, despite the clear relevance of this information to weed management. This is partly due to differences between different sources of information, e.g., NSW Flora online (PlantNET) may not include plants known to be present in the state if they have yet to become established (i.e., pre-naturalised), whereas the rapid growth of citizen science platforms such as iNaturalist has provided an unprecedented source of putatively pre-naturalised and naturalised plant occurrence records.

A review of all available information is needed to definitively characterise what plants are naturalised and pre-naturalised in NSW. Here, we report on a checklist of the non-native vascular plants of NSW as of 2024, produced by data compilation followed by expert manual curation and annotation. We combined information from PlantNET, iNaturalist, and the Australian Plant Census using the R package APCalign. A panel of experts curated the resulting list and annotated each taxon with degree of establishment and geographic distribution in NSW. We recommend that this list be considered authoritative as of 2024 and expect to provide regular updates. We emphasise that not all plants listed will become weeds, and reiterate that the list is one resource that policy and management tools (such as the New Weed Incursion Plan) can draw on to help understand which plants will be the weeds of the future.