Q: We need to trim this schefflera back. What is best?
A: A schefflera can usually recover nicely from severe pruning but needs to be in bright shade, probably outdoors, in order to sprout new limbs faster.
The best time to do the pruning is late April thru mid-summer if you plan to take it outdoors. You can actually prune it at about three feet high despite it being so tall now.
Fertilize at half-strength and put it in bright shade outdoors. It should sprout a new green top by fall.