rhizome vs rootstock

rhizome and rootstock both are nouns.

Word	Noun	Adjective	Verb	Adverb
rhizome	Yes	No	No	No
rootstock	Yes	No	No	No

As nouns, rhizome and rootstock are synonyms defined as:

rhizome and rootstock: a horizontal plant stem with shoots above and roots below serving as a reproductive structure

Other synonyms of rhizome include rootstalk.

rhizome (noun)	rootstock (noun)
a horizontal plant stem with shoots above and roots below serving as a reproductive structure	root or part of a root used for plant propagation; especially that part of a grafted plant that supplies the roots
	a horizontal plant stem with shoots above and roots below serving as a reproductive structure