I don't have a big personal interest in poetry, but to add someone to the list of scientists who were also part-time poets, I'd like to submit J. Robert Oppenheimer.

I'm currently reading his biography (the Sherwin & Kai one, 2/3 of the way through and it's great so far) and they often mention his interest in poetry and literature, and also that he wrote some poetry himself (though not many examples are given in the book).