IME clowns will host whatever they feel like. Mine has hosted in my GSP, green hairy mushrooms and frogspawn. He was in my small GBTA for a little bit but then moved into the frogsawn (I think because the GBTA is still pretty small). My clown also hosted nothing for the first 6 weeks in the tank. Be patient he will host when he wants to. But if this is the anemone you have it doesn't sound like it's hostable anyway.
http://www.liveaquaria.com/product/p...cfm?pCatId=630
HTH