Usually the most efficient and natural-looking method is to place real leaves or props in the scene and photograph them in-camera. That gives you correct shadows, perspective, and lighting automatically, which is often faster than building everything later in Photoshop.

If the subject may disturb the setup, a common solution is to shoot multiple frames from a tripod: one with the subject, another with the scattered objects, then combine them with masking. This keeps the background aligned while letting you control object placement.

Some photographers may duplicate a few leaves in post, especially for Instagram where small screens and quick viewing hide minor edits. But fully compositing every object is usually more time-consuming and can look less natural unless done carefully.

For the best results, prepare the leaves/props in advance, secure them if needed so they do not move, and control the light so the scene looks consistent. In short: most of the scene is often real, with selective compositing or cloning used only to refine it.