Help with schefflera shedding

I have a schefflera outside that I may (definitely) have neglected to water sufficiently during the heat wave, and now it's lost most of its bottomed leaves! What do I do to save it? Can I prune it all the way down to stimulate regrowth?

 

Welcome to the Forums!

Indeed you can.
Cut mine back in early June: here it is today.

 

Same plant, this afternoon.