Threatened exotic species of botanical gardens: Application of trait-based naturalized species risk scoring assessment

•Botanical gardens contain exotic species that may also have important conservation status, that lead to the importance of invasion risk assessment.•Framework-based scoring assessment, such as Tropical Weed Risk Assessment Procedure (TWRAP) of invasion risk of botanical garden exotic species is a simple and practically implementable for invasive species risk assessment in botanical gardens.•The climate suitability and seed traits were considered as the main source of scoring variability between assessors in this study that directly contribute to the TWRAP score results uncertainty.•Invasive species risk assessment is crucial to be conducted for botanical garden exotic species with important conservation status, to allow botanical garden management to properly managed the risk of invasion while at the same time conserve these threatened species as botanical garden species.