The seasonal shedding of leaves here is odd if you are used to a British Autumn, for example. The Jacaranda tree outside our house takes all season to shed its leaves and then the stalks fall off in Spring. In the UK, the leaves seems to drop off overnight.
As UK Man says, it's possible that the leaves will come back.
Looking at our Gardenia without knowing which month it is I'd swear it was Autumn instead of Spring. The last few weeks its leaves started turning yellow and fall off. You have to look closely to see there's new leaf buds forming.