Climate change is emerging as a top threat to biodiversity in the 21st century. For plants there are alarming projections of species declines, range shifts, and the disruption of important biotic interactions such as with pollinators and mycorrhizal fungi. Understanding the nature and magnitude of these changes will be key to limiting biodiversity losses and managing well-functioning ecosystems going forward. This talk will explore the ways in which changing climate is likely to affect plant diversity in New England and beyond, how species are adjusting (or failing to adjust), and the ways that biotic interactions might facilitate or hinder these changes. Observations from native plant horticulture provide unique opportunities to gain insight into some of these ecological dynamics, as well as to begin grappling with updates to our values and terminology around “native” vs. “non-native” species in a rapidly changing world.