Iffen you're itching to get petals really quick, and don't mind a little cheatery, you can always edit a save game^^. Take note how many petals of each color you have, then open the save in notepad (or some such editor), use the search function to scan for the petals by colour, but compare the amount to what you have in your inventory to find the right entries. The save file also has other petals, that are part of loot bags or those in the bazaar.