In the middle of Rayol (which is quite small) you'll see signs leading you to "Le Domaine du Rayol". It's not cheap (about EUR 7 p.p.) but worth it. You can spend several hours in this park and walk through different zones.
There is a Chinese bamboo garden, fern trees from New Zealand, palm trees from the Canaries, Mexican rock garden, eucalyptus from Australia, different plants from Chile, South Africa or California.