Marchita comes from the verb marchitar, meaning to wither or fade. It's often used for plants or flowers, but in this song, it's applied to emotions.
The lyrics repeat "Se marchita tu corazón" (Your heart withers), vividly portraying the pain of a love that has died due to betrayal. This metaphorical use makes the word particularly poignant and memorable.
Armonía 10 brings us a classic cumbia tune about getting over a bad breakup. The singer is done with this person, saying "precisamente hoy mismo quiero que se vaya" [precisely today I want them to leave]. They're actively trying to forget them, repeating "estoy buscando manera de olvidarla, quiero olvidarla que no vuelva más" [I'm looking for a way to forget her, I want to forget her so she never comes back].
It sounds like this ex really did a number on them! The lyrics lament how their love, once strong, "se ha marchitado por otro querer" [has withered because of another's love]. All that's left of their kisses is "el aroma" [the aroma] – a pretty poetic way to say it's all gone. The singer calls it "un falso amor" [a false love] because the ex "no valoraba nunca nunca mi cariño, se burla se río de mí" [never, ever valued my affection, they mocked me, they laughed at me]. Ouch! This song is all about shaking off that hurt and moving on.