Your fruit trees don't know it's winter
I don't know about you, but it is mid July and my fruit trees are clueless about what season it is. My dwarf black mulberry tree is actually fruiting (it is supposed to be fruiting in October/November) and the pomegranates are joyously pumping out new leaves. The figs, silvanberry and plums are still in leaf. Folks, this is NOT normal for this time of year! So what can we do?
Simply strip the leaves of your deciduous trees to force/trick them into dormancy. What this does is encourage the hormone Gibberellin - the initiator of flower bud formation - which then leads to fruit production. The colder it is during dormancy, the more Giberellins.
If you live in coastal Perth or far away from the Hills area where it doesn't get frosts or below 5C at night much, choose low chill fruit varieties when buying deciduous trees. Even if it is really cold at night, warm daytime temperatures will often cancel out that precious chill factor required to set flowers and fruit like plums, apricots, peaches, apples etc. Another hint is to locate your fruit trees away from heat retaining walls, paving and fences.