Some clowns would start hosting corals if there is no anemone present in the tank. But if you want your clowns to host something, the anemone would be your best chance. It isn't very often that clowns will host corals.
My clownfish hosted a toadstool for a long time before finally moving to a bubble tip anemone. Funny thing was the clown pair came with the Anemone. I bought them all as a "set".