Hermione had taken his hand again and was gripping it tightly. He could not look at her, but returned the pressure, now taking deep, sharp gulps of the night air, trying to steady himself, trying regain control. He should have brought something to give them, and he had not thought of it, and every plant in the graveyard was leafless and frozen. But Hermione raised her wand, moved it in a circle through the air and a wreath of Christmas roses blossomed before them. Harry caught it and laid it on his parents’ grave.
Harry Potter and the Deathly Hallows
One of my favorite scenes.