wild hydrangea vs hydrangea

wild hydrangea and hydrangea both are nouns.

Word	Noun	Adjective	Verb	Adverb
wild hydrangea	Yes	No	No	No
hydrangea	Yes	No	No	No

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

wild hydrangea: deciduous shrub with creamy white flower clusters; eastern United States
hydrangea: any of various deciduous or evergreen shrubs of the genus Hydrangea

wild hydrangea (noun)	hydrangea (noun)
deciduous shrub with creamy white flower clusters; eastern United States	any of various deciduous or evergreen shrubs of the genus Hydrangea