shrivel up vs die back

shrivel up and die back both are verbs.

Word	Noun	Adjective	Verb	Adverb
shrivel up	No	No	Yes	No
die back	No	No	Yes	No

As verbs, die back is a hyponym of shrivel up; that is, die back is a word with a more specific, narrower meaning than shrivel up:

Other hyponyms of shrivel up include atrophy, blast, die down, dry up, mummify.

shrivel up (verb)	die back (verb)
wither, as with a loss of moisture	suffer from a disease that kills shoots