Ornamental horticulture is the primary pathway for invasive alien plant introductions. We
critically appraise published evidence on the effectiveness of four policy instruments that
tackle invasions along the horticulture supply chain: pre‐border import restrictions, post‐
border bans, industry codes of conduct and consumer education. Effective pre‐border
interventions rely on rigorous risk assessment and high industry compliance. Post‐border
sales bans become progressively less effective when alien species become widespread in a …

Ornamental horticulture is the primary pathway for invasive alien plant introductions. We
critically appraise published evidence on the effectiveness of four policy instruments that
tackle invasions along the horticulture supply-chain: pre-border import restrictions, post-
border bans, industry codes of conduct, and consumer education. 2. Effective pre-border
interventions rely on rigorous risk assessment and high industry compliance. Post-border
sales bans become progressively less effective when alien species become widespread in a …