After the quest, you can get another pretty flower from My Arm, and present it again to Pretty Flower or to his son Sparkly Crystal, but this appears to be just for humour and does not give any reward.
He wanted his son to have a fearsome name, but became disappointed when he attempted to eat a sparkly crystal, as he knows that he will have the same problems as him when he grows up.
His name contrasts his appearance and reputation, as he is formidable and ugly.
As trolls are named after the first thing they attempt to eat, he must have eaten a pretty flower.
He has more pieces of rock in front of his mouth (possibly teeth) than most trolls.