The vast majority of what we call "wild flowers" are introduced or escaped. Change is what life is all about. People seem to think life and the environment should be static, like a picture in a garden magazine. But river and stream banks move, plant communities constantly change in adaptation to climatic differences from year to year, new plant species move in all the time, established plant species move on to somewhere else or fade into the background, even the global climate changes dramatically over the geologic time scale with or without our extra carbon.
I'd like to think people are capable of realizing the complexity and interconnection of the natural world, but sometimes I wonder. . . .