Boy/man action love

From Tokyopop:
Will Anderson is the nephew of the modern-day Al Capone. He lives in New York, goes to a ritzy private school, and dotes on his charming little cousin Kate. Until one day, when he runs into a man and his pet penguin in Central Park (or rather, the man steals his hot dog), and then everything starts to get a little complicated. Suddenly Will is swept up into the buisness of the Trash Company, an odd-jobs outfit whose main work tends to involve stolen jewels and a whole lot of troub

Kaito Yagami is a florist/gardener by day and a hired assassin by night. He kills using plants to make money to care for his brother who is confined in a hospital.