The plants we choose to cultivate shape our landscapes, ecosystems, and future. For centuries, the global movement of plants—driven largely by horticultural trade—has introduced species that cause significant harm. Many invasive plants continue to spread unchecked through the nursery trade, escaping gardens to outcompete native species, disrupt food webs, and alter ecosystems. Beyond ecological damage, these species can threaten agriculture, increase fire and flood risk, impact human health, and impose significant economic burdens. In this session, we will explore how invasive plant introductions are deeply tied to history, trade, and regulation—and why slowing their spread requires a proactive, preventative approach. We’ll examine the geohistory of floral distribution, the role of plants in ecosystem stability, and the ongoing consequences of an inconsistently regulated plant trade. Participants will gain insights into the need for stronger policies, the importance of responsible gardening, and actionable steps to help curb the introduction and spread of invasive species. By closing the garden gateway, we can protect biodiversity, support resilient landscapes, and safeguard our shared environmental, economic, and personal well-being. Join us in rethinking how we cultivate and steward the plants that shape our world.

Cathy Kavassalis is a Master Gardener from Ontario, Canada, and co-founder of the Canadian Coalition for Invasive Plant Regulation. With over 20 years of experience in horticulture and environmental advocacy, Cathy is passionate about promoting sustainable gardening practices and reducing the spread of invasive plants through the nursery trade. A skilled educator and speaker, she has delivered compelling presentations on topics such as “Invasive Plants: How Master Gardeners Can Address the Challenge” and “Greening the Future: A New Era of Horticulture.” Known for blending scientific rigor with practical, actionable advice, Cathy inspires gardeners to embrace biodiversity-friendly practices and create gardens that contribute to environmental resilience. Her work empowers individuals to make meaningful contributions to safeguarding ecosystems and protecting the planet.