What is the fine-grained topic of the following text: The Roseraie’s vision, at the height of its flowering season, with its riot of colours, forms and structures, must not detract from the fact that the garden is composed, aside from the lawns which are there as a setting for the roses and the boxwood borders giving structure to the scene, of nothing but roses. Only return the topic.
The Roseraie Garden's composition and features