There are around seventy varieties of hydrangea trees, which are differentiated by their respective leaf forms and blooms. The four most common varieties of hydrangeas are classified as mophead/lacecap, oak leaf, paniculata and Annabelle.
Hydrangeas are most commonly white, but they also occur in a variety of colors, including red, blue, purple and pink. Coloration is usually determined by the type and acidity of the soil in which the hydrangea is grown. Bloom shapes also vary from species to species and even within the same species. Hydrangeas are also different from region to region and can be found in Asia, the Americas and parts of Europe.