The speaker is carrying secrets they've never shared, and they're torn about whether to let them go. They imagine doing it in the loudest, most public ways: shouting from rooftops, screaming, launching the secrets as paper planes so someone will find them on the ground. The image is playful but also a little desperate, as if the speaker wants to be found.
The hopeful tone doesn't last. The speaker says they will insist the secrets are true, then admits they expect not to be believed. Others will laugh and look away, never really seeing the pain in their eyes. The mood slides from longing to quiet resignation. The final line is the most striking: "I think that's my fault." Rather than blaming the people who ignore them, the speaker takes the blame, perhaps because they've stayed silent for so long. The poem leaves us with loneliness and a heavy sense of self-blame, and the title's discarded flowers seem to echo that feeling of giving up.