>>24465520 (OP)Authors who are primarily poets usually write good prose. (Sometimes they overdo the richness. Emily Dickinson's letters are a bit like that. So is Dylan Thomas. You want to say, look, if you feel like that, just write a poem already.)
On the other hand, when people who are primarily prose writers try their hand at a little verse, it's usually pretty bad. (Nabokov for example.)
There must be someone who wrote decent poetry but terrible prose. Let's think.
Someone criticized some newspaper article of Ezra Pound's, saying, "if a poet is going to turn journalist he has to write decent prose, and Mr. Pound's prose is about the ugliest I have ever read" or something.
He was wrong though. E.P. was a fine fellow. (Of course some people would say E.P. doesn't count in this category because he didn't write good poetry, but that's another argument.)