Also known as the Summer Lilac, Buddleja Davidii, the Butterfly Bush can grow roughly to the size of 3 to 5 feet.
It is a rapidly growing perennial shrub that grows huge flower spikes on it.
It blooms during the summertime and the best time to plant them in Spring, or Fall.
To answer shortly: Scrophulariaceae
That family is more commonly known as the figwort family. The plants from this family are both annual and perennial herbs, as well as shrubs. the Flowers have a bilateral shape, or are rarely radial symmetric
The Scrophularia, Figworts, Verbascum, Mulleins are multiple other plants in the figwort family.
They are native to Central China. They are highly invasive, and should not be kept outside of gardens and nature parks. Due to their ability to grow rapidly, and spread rapidly.
The plant has medicinal properties including Diuretic, Anti-inflammatory, Antispasmodic, Promotes Bile Flow, Antioxidant, Hepatoprotective, and it is Antiviral.
This guy: Botanist Reverend Adam Buddle discovered the plant.
Although the beautiful and eye-catching plant seems hardly harmless, it is actually extremely harmful to the environment. It harms the health of the local ecosystems, because it grows so quickly it strips the land of water, and needed nutrients.