Marchitaron is the past tense of marchitar, which means "to wither" or "to fade". It's a beautifully poetic word that you won't hear in everyday conversation.
In the song, Nicki Nicole sings "No me duele más, se marchitaron las rosas" (It doesn't hurt me anymore, the roses withered). She uses this powerful image to signify that her love and feelings for her ex are completely dead, like a flower that has lost its life and color. It's a much more evocative way of saying a romance has ended.
In "Ojos Verdes", Argentine artist Nicki Nicole is completely done with an ex, and she makes sure he knows it. Instead of drowning in heartbreak, she drops the drama with zero effort: "pa' olvidarte, no hizo falta alcohol ni fiesta" ("to forget you, I didn't need alcohol or partying"). Notice how she sings "pa'" instead of "para"—that is super common spoken Spanish everywhere. She also uses Argentine phrasing with vos instead of tú, like "vos me pienses" ("you think of me") and "soñás" ("you dream"). The core sting of the track is knowing that while he has already moved on to someone new, he is still stuck on her: "Sé que estás con otra, pero pensando en mí / Y le das los besos que algún día te di" ("I know you are with another girl, but thinking of me / And you give her the kisses I once gave you").
The title itself delivers the ultimate mic drop. She tells him, "Suerte encontrándome en otros ojos verdes" ("Good luck finding me in other green eyes"). It is blunt, petty, and wildly confident. She isn't crying over faded love anymore—as she puts it, "se marchitaron las rosas" ("the roses withered"). When she delivers lines like "No te deseo lo mejor, porque ya me perdiste / Pero que te vaya bien con lo que conseguiste" ("I don't wish you the best, because you already lost me / But good luck with whatever you ended up with"), she turns closure into pure victory. He wanted to look like the one who got away, but she closed the door for good.