trim back vs cut back

trim back and cut back both are verbs.

Word	Noun	Adjective	Verb	Adverb
trim back	No	No	Yes	No
cut back	No	No	Yes	No

As verbs, trim back and cut back are synonyms defined as:

Other synonyms of trim back include bring down, cut, cut down, reduce, trim, trim down.

trim back (verb)	cut back (verb)
cut down on; make a reduction in	place restrictions on
	cut down on; make a reduction in
	cultivate, tend, and cut back the growth of
	return in time