Assuming it's a Ageratina havanensis, you should feel very lucky! Mine are covered with buds right now and will soon burst into bloom - just in time for the fall migration of butterflies. These shrubs, along with purple eupatorium odorata (which has been given a new name that I can't remember), are absolute magnets to butterflies headed south. The Butterfly Festival in Mission Texas reports that more than two dozen butterflies have been recorded using this plant.
As your wonderful photos prove, it's also a great source of nectar for bees.
