Hydrangea, also known as hortensia is a genus of 70-80 species of plants native to Asia and the Americas. In most species the flowers are white, pink, red, blue or purple. While most species benefit from some shade, too much shade can reduce flowering. The mophead hydrangeas are most well-known for their ability to change color, depending on where it's planted and how it's fed. Bloom time: spring, summer, fall.