About 20,000 roses in 60 varieties can be admired at Rozarium in Park del Oeste. Its center is a pond with beautiful specimens of water lilies and a fountain with a sculpture of a nymph. Every year a competition is organized here for the most beautiful varieties of roses (Concurso Internacional de Rosas Nuevas de la villa de Madrid).
Varieties that win distinction become part of the collection. The winners included, among others: "Ingrid Bergmann", "Frisson Frais", "Chartreuse de Parme" and "BAR 6953". Varieties of Spanish roses are also represented in large numbers, e.g. "Countess Mayalde", "María Ribas de Bañuls" and "Dorita".
Rozarium was designed by Ramón Ortíz in 1956. In 2006, it was awarded by the World Federation of Rose Societies, which recognized that it is one of the most beautiful collections of roses in the world. Breeders from around the world take part in competitions taking place here.