Suggested answer:
It does not take long to establish that this poem lacks cohesion. If we look for signals in each line, pointing either forward or backward to other items in the poem, we get some unexpected results. The relative pronoun which in the second line, for instance, would normally be a good indicator of cohesion, but not in this text. Which cannot, for semantic and contextual reasons, be seen to point back to sky, although this is what is implied by the syntax. The poem not only lacks pronominal cohesion, but neither is there any lexical cohesion; we can simply not make sense of the poem, even if we could argue that roses, perfumes and idylls could breathe, it is quite clear that the lines have been put together at random to create a puzzling rather, than meaningful, effect.

---

Read about cohesion here and cohesive ties here.
Terminology: cohesion, cohesive tie