Capomos are the flowers of the breadnut tree (Brosimum alicastrum), a plant native to certain regions of Mexico. This word is the central metaphor of the song, which is titled "Flor de Capomo" (Capomo Flower).
In the lyrics, the singer compares the young woman he loves to these beautiful, blossoming flowers. He sings, "linda vas creciendo como los capomos" (you are growing beautifully like the capomos), using this unique piece of natural imagery to express her burgeoning beauty in a truly poetic way.
This song is a classic, sweet declaration of love from a man to the woman he's trying to win over. He calls her his "Trigueñita hermosa" (beautiful brunette) and compares her to a blooming flower, saying she's growing "Como los capomos que se encuentran en la flor" (Like the capomo flowers that are in bloom). It's all about the early, exciting stage of a romance, where he's openly telling her, "Te ando enamorando con grande fervor" (I'm trying to make you fall in love with me with great passion).
What's really charming is how he describes his plan to visit her family. He says, "Mañana o pasado yo voy a tu casa / Tu mamá te ordena una silla para mí" (Tomorrow or the day after, I'm going to your house / Your mom orders a chair for me), which shows this is a serious, old-fashioned courtship. He then gives her a playful instruction for when he arrives: "finge no mirarme / Ponte muy contenta porque estoy aquí" (pretend not to look at me / Be very happy because I'm here). It's like they share a secret understanding, even while following tradition.