Hydrangea is a water fairy who appears exclusively in the Nintendo DS game Disney Fairies: Tinker Bell and the Lost Treasure, with no previous appearances under her belt.
Hydrangea appears to simply be a water fairy reskin of Qana's model from the previous game, even having a similar dress and body structure, however her face may be more reminiscent of that of the previous game's Dewberry character.
Disney Fairies: Tinker Bell and the Lost Treasure
Hydrangea is the basic type of non-player character in the game's Story Mode, however if the player chooses to use the Water Talent in the Fairy Mode, her role becomes slightly more important. She provides the player some some of the talent's tasks, and once all completed, the player may speak to her to practice these skills at any time.