Some years back I took an evening course led by a poet who is also a Steiner teacher - in fact the classes took place at the local Rudolf Steiner school. It was at least partly based on a book by Paul Matthews called Sing Me the Creation, which is centred around four types of sentences.
Of course poets don't always use sentences at all. We can write in fragments, or lists. But it is hard to think of any sorts of sentences other than the four that Matthews describes - the statement, the command, the exclamation, and the question.
I started thinking about these four again while reading the poetry of Olena Kalytiak Davis recently. Most poems that I read, if they are written in sentences, rely heavily on statements. (Sometimes fairly strange statements, but statements nevertheless). In Davis's poetry, I found many many examples of commands, questions, and even exclamations, and I think it is one of the reasons I find her poetry so powerful.
For instance, "In Defense of Marriage" consists mostly of commands:
Marry the white fences;
marry the fenceless
Moon and the defenceless sky
Promise to forsake.
to the cistern full of asters
The final statement seems stronger for its position at the end of a string of commands:
I married the way moths marry.
I married hard.
And then there are her questions, like this one from "The Panic of Birds"
What was it
I understood so well last night, so well it kissed me,
Sweetly, on the forehead?
The exclamation is the hardest, I think, to use effectively. Nineteenth century poems are full of them, of course - the word "Oh!" is a give away. It's one word that some beginners use misguidedly to make their work seem more "poetic" and one word that puts editors off enormously. (See the introduction by Billy Collins to Best American Poems 2006)
Davis makes very effective use of "O'" in her poem "In the Clear Long After" (which is included in the first Poetry Daily anthology. The last two lines are
O, to be stung by an errant bee. O, to sting.
O, to see you again. Covered in spring.
There are poems by Davis that I love, and poems that leave me mystified, although I am decreasing the number of those as I get to know them better. She's a little known poet but one I believe is worth becoming acquainted with. The Paul Matthews book is well worth a read, too.