Put simply, ‘exotics’ are any non native or introduced plants. Non native plants didn’t evolve as part of the local ecology. They certainly had interconnected relationships to the flora and fauna of their home range, but are unlikely to have interdependent relationships where they are introduced. Because they do not serve as part of the system while at the same time displacing native plants that DO serve we must approach the planting of exotics with a critical eye. We must ask how they bring value if any.
What service does a non native plant provide? If it provides no service, other than how it looks, then yes, the net result of it taking up space in the landscape is bad. However when exotics do provide a service that a native plant cannot, then its addition to the landscape can be positive. Perhaps it is a cognate of a native that is no longer available but is needed for a particular eco-service. Perhaps it's food. Perhaps it inspires. Do magnolias remind you of your grandmother and bring you joy? Great, let’s plant some magnolias! After all,happiness is a fundamental need.
If it brings joy, then we must ask if it is invasive? An exotic is considered ‘invasive’ when it can thrive and out compete natives in a landscape where it is introduced. No amount of personal joy justifies planting invasive plants. No pampas grass, no morning glory, no ivy. Period.
All exotics must be intentionally vetted before they can be planted. The judicious use of exotics is fine if they truly serve us in a way that no native can. Otherwise, rebuild the ecosystem with natives!
Does it have to be all native plants we plant? No, it is scalable. The more native plants there are, the better the system functions but our lands must also balance our need for food, shelter, and enjoyment. Until recently, landscape design only factored in our needs at the expense of the needs of ecological systems. Edenism is the belief that we can have both healthy ecologies AND have all our needs and fancies met. If non native plants provide for our basic needs or bring us joy then they are welcome just not at the expense of overall balance. We will have our cake, and eat it too.