Is the Butterfly bush a perennial?

The Butterfly bush (Buddleja davidii) is typically considered a perennial plant, but its hardiness can vary depending on the climate. In warmer regions (USDA zones 5-10), it often behaves as a perennial, dying back in winter and regrowing in spring. However, in colder climates, it may not survive harsh winters without protection. Overall, it is best treated as a perennial in suitable areas.