Five short lines carry a quiet love poem. The speaker starts with flowers that bloom only at night, then flowers that bloom only in fall, then flowers that last just a short while in fall. Each line narrows the field, making the flower rarer and more fragile. Then comes the turn: "To me you are one of those flowers." The person addressed is special, perhaps hard to catch, and maybe not meant to stay forever.
The last line shifts from comparison to confession. The speaker's days were "like a desert," empty and dry, until this person arrived and made them a garden. The feeling is gratitude mixed with tenderness. The mood is gentle and hopeful, but there's a faint sadness too. The repeated stress on brief blooming hints that the speaker knows this happiness may be fleeting, which makes it feel even more precious.