Is it a recently acquired bush? If so then it may well have flowered in May/June, but it is too late to be flowering now, and you will have to wait until late spring/early summer 2009. If it is not a new bush and you know it has flowered before then it may well need feeding next spring when it starts it's new growth.
rhodis and camellias start to make their buds for next year between now and the end of august. During this time feed and water them well with ericaceous fertiliser. Both are susceptible to blind shoots or bud drop if they are kept dry nowm so have them in well drained moisture retentive (stays damp but doesn't flood)ericaceous soil and make sure to water them well