What marks a poet out? Vernacular rhetoric
How is it that when we read, 'Let each new hero come', we know that it is Seamus Heaney? Or what about 'the blossom of light'? What makes that so obviously Mary Oliver?
Harold Bloom said that to understand the meaning of a word as a poet uses it, we must be familiar with all of their writing, to see how the word gets meaning in the way that poet uses it.
That's partly the answer. Blossom is a very Mary Oliver word. 'In April/the ponds open/like black blossoms.'
Seamus Heaney made an art of using vernacular speech in a way that was unique to him. He turned local language into rhetoric. He turns nouns into adjectives in compounds, like Keats did: sky-born, world-tree, ocean-deafened.
This is part of the effort to make the vernacular, rhetorical. 'The hammered shod of a bay', is a classically Heaney line. It takes something plain and earthy, almost a description of physical work, but it makes a verb a noun. That is so simple that it almost sound like the ungrammatical speech of a Wordsworth character.
Mary Oliver pulls the same trick, using the word blossom as if she were a poet ('the blossom of the rising moon'), when in fact she is a naturalist. Blossom opens and falls the way a moon waxes and wanes.
No-one actually talks like that, this is rhetoric after all, but they pull it from the vernacular and make it sound so close to the vernacular that you sometimes forget they are talking as poets at all.
The paradox is that that is exactly how you know who they are. The great model for this sort of writing is not Wordsworth at all, but Robert Frost.