What do hydrangeas symbolise? In brief: The meaning of hydrangeas varies culturally. In Japan, they signify heartfelt emotion and apology, while in Europe, they symbolise arrogance and vanity, with a historical belief linking them to singlehood.

In Japan, the flower is associated with heartfelt emotion, understanding and apology. The Japanese emperor apparently made a lasting impression not only on his girlfriend's family but also the rest of his empire. The hydrangea can further symbolize unity and togetherness.

If you don't prune hydrangeas then they can eventually resemble a tangled mass of woody stems, and the flowers will become smaller and less showy. Regular pruning of hydrangeas helps to maintain their shape and also encourages new growth and a better display of blooms.

Noyes from Gardening Chores says you should never try to plant hydrangeas in zones 1 and 2 due to extremely cold temperatures. "Similarly, it is hard to grow hydrangeas in very hot areas of the country; their heat tolerance ranges from zones 8 and 11 (but it is usually 9), according to the variety.