Stars look effortless and beautiful from far away, but the speaker points out what they really are: burning balls of fire, some as hot as 30,000 K. Even so, people adore them, search for them, and even buy and sell them. The comparison to flowers gives the idea a gentle twist. Both are everywhere, all different, and both are praised without much thought for what lies underneath.
That "except" is where the poem turns. The speaker seems to see themselves in the stars: something that may be burning or struggling inside, yet is admired from a distance. The short, clipped lines ("searched for. / bought. / sold.") slow the poem down and add a quiet unease, as if being loved and being treated like a possession are close together. The ending is plain and open. The speaker wants to be admired, yearned for, and loved forever. The mood is tender and wistful, with a little ache of loneliness underneath.