wild indigo vs woody plant

wild indigo and woody plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
wild indigo	Yes	No	No	No
woody plant	Yes	No	No	No

As nouns, woody plant is a hypernym of wild indigo; that is, woody plant is a word with a broader meaning than wild indigo:

wild indigo: any of several plants of the genus Baptisia
woody plant: a plant having hard lignified tissues or woody parts especially stems

Other hypernyms of wild indigo include ligneous plant.

wild indigo (noun)	woody plant (noun)
any of several plants of the genus Baptisia	a plant having hard lignified tissues or woody parts especially stems