Three short lines carry a surprisingly heavy moment. The speaker and someone else, since the poem says "we," need to get to the other side of a street, and the only way across is over a patch of flowers. Nothing dramatic happens. They simply do it, and the poem reports it plainly.
That plainness is what gives the poem its feeling. The word "had" suggests they saw no other choice, yet "crush" is a rough, deliberate verb, and it makes the damage hard to ignore. The speaker doesn't say they feel guilty, but the fact that the moment is worth recording hints at a quiet discomfort. The mood is subdued and a little sad.
Read more widely, the lines can suggest how everyday convenience, or necessity, often comes at the expense of something delicate and beautiful. The poem leaves that thought for the reader to finish.