Both of these elements combined make them an invasive plant.
Butterfly bushes—a monster in our midst
Let me pitch you a movie.
The scene opens in a front yard in suburbia. It’s morning—the sun is rising, turning the clouds a gentle pink. We see a beautiful garden in the front yard, with several butterfly bushes swaying in the breeze.
It’s fall, and the once-purple flowers are turning into seed pods. In a few weeks, each long branch will end in a clustered cone.