Hydrangea is a symbolic flower of Nagasaki, Japan.
According to the website below, there are several languages of this flower.
Heartfelt and honest emotions of any kind
Gratitude and thanksgiving to someone else
Developing a deeper understanding between two people
Heartlessness and acting without thinking about the feelings of another
Frigidity and disinterest in a romantic proposal
Boasting and bragging about false accomplishments
Abundance and prosperity
Grace and beauty, sometimes taken to an extreme of vanity and narcissism
the 4th wedding anniversary for a couple