Rosa vs. rosado
Both rosa and rosado translate to "pink" in English, but they function differently grammatically and geographically. While rosa refers directly to the flower and is often used as an invariable color adjective, rosado is a standard adjective describing a rosy hue or tint. Generally, rosa is more common in Spain, while rosado is frequently preferred in many Latin American countries.
Rosa
A1This word functions as both a noun (the flower) and an adjective (the color). When used as an adjective, it refers to the natural color of the rose. In strict grammar, rosa can remain unchanged even when describing plural nouns (e.g., camisas rosa), though in modern usage, primarily in Spain, it often becomes plural (e.g., camisas rosas). It describes the color pink in a general sense.
Me compré una camisa rosa para la fiesta.
(I bought a pink shirt for the party.)
Sus zapatos son de color rosa brillante.
(Her shoes are a bright pink color.)
Las paredes de mi habitación son rosas.
(The walls of my room are pink.)
No me gusta el vestido rosa.
(I do not like the pink dress.)
Pon el lazo rosa en el regalo.
(Put the pink ribbon on the gift.)
Rosado
A2This is a standard adjective derived from the rose, meaning "rose-colored" or "pinkish." Unlike rosa, rosado always changes its ending to match the gender and number of the noun it modifies (becoming rosada, rosados, or rosadas). It is widely used in Latin America to mean pink and is the exclusive term used everywhere for specific items like rosé wine.
Prefiero beber una copa de vino rosado.
(I prefer to drink a glass of rosé wine.)
El cielo se puso rosado durante el atardecer.
(The sky turned pink during the sunset.)
Esas flores tienen unos pétalos rosados muy bonitos.
(Those flowers have very pretty pink petals.)
La niña tiene las mejillas rosadas por el frío.
(The little girl has rosy cheeks because of the cold.)
Vimos un flamenco rosado en el zoológico.
(We saw a pink flamingo at the zoo.)
Summary
Use rosa if you are referring to the color in a general sense or if you are in Spain using it as a direct adjective. Use rosado if you are describing something with a rosy tint, referring to rosé wine, or if you are in Latin America where this version acts like a standard descriptive adjective that changes based on gender and number.