Flowers is a short warning about the cost of taking something beautiful for yourself. The speaker says a wise person never picks the flower that glows brightest, because the best rose in the garden is the one most likely to be harmed by being chosen. The poem then imagines two fates for a picked flower. It can be kept in a vase, admired by one person while its petals slowly wilt, or it can be thrown away and left to the wind.
Either way, the ending is the same: the flower dies. The last lines, "You left them there / Just to die," land with quiet guilt, as if the picker only realizes the damage by morning. The mood is gentle but regretful, almost like advice from someone who has seen this happen. Judging by how the poem speaks of the flower as "them," it may also be about people, and about loving or possessing someone in a way that destroys what you admired in them.