hortensia vs hydrangea

hortensia and hydrangea both are nouns.

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

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

hortensia: deciduous shrub bearing roundheaded flower clusters opening green and aging to pink or blue
hydrangea: any of various deciduous or evergreen shrubs of the genus Hydrangea

hortensia (noun)	hydrangea (noun)
deciduous shrub bearing roundheaded flower clusters opening green and aging to pink or blue	any of various deciduous or evergreen shrubs of the genus Hydrangea
very tall branching herb with showy much-doubled yellow flower heads