Why is lemon tree not fruiting after hard pruning?
We are in southern California, County Of Los Angeles. We use to get lots of fruit on this lemon tree.
Hard pruning is detrimental. It is extremely stressful for the plant physiology as well as you probably cut off all the flower buds. If the plant survives, which is not a sure thing, then you will have to wait for it to refoliate and bloom again. It could take a year or two. Hopefully you have not exposed the woody stems to direct SoCal intense summer sunlight and sunscald of the bark and underlying tissues. That can set it up for wood decay and structural collapse. The only thing you can do is to water and fertilize and wait and see