How do you cure cursed trees in okami

In Sei-An city, you must heal all 20 uncursed trees. After that you have to go to the house in the north-east corner (the aristocratic qtr.) and find Mr. Blossom. If you have cured all 20 uncursed trees, then you talk to Mr.B, he'll start running around town temporarly uncursing some trees. After he uncurses one, you have to make it bloom quickly. After you do that he'll move to the next one. Careful though, he moves really fast and you don't have much time.