grow together vs combine

grow together is not a noun while combine is a noun.

Word	Noun	Adjective	Verb	Adverb
grow together	No	No	Yes	No
combine	Yes	No	Yes	No

As verbs, combine is a hypernym of grow together; that is, combine is a word with a broader meaning than grow together:

Other hypernyms of grow together include blend, coalesce, commingle, conflate, flux, fuse, immix, meld, merge, mix.

grow together (noun)	combine (noun)
	harvester that heads and threshes and cleans grain while moving across the field
	an occurrence that results in things being united
	a consortium of independent organizations formed to limit competition by controlling the production and distribution of a product or service

grow together (verb)	combine (verb)
grow together (of plants and organs)	mix together different elements
	put or add together
	combine so as to form a whole; mix
	gather in a mass, sum, or whole
	add together from different sources
	join for a common purpose or in a common action
	have or possess in combination