blue sage vs big sagebrush

blue sage and big sagebrush both are nouns.

Word	Noun	Adjective	Verb	Adverb
blue sage	Yes	No	No	No
big sagebrush	Yes	No	No	No

As nouns, blue sage and big sagebrush are synonyms defined as:

blue sage and big sagebrush: aromatic shrub of arid regions of western North America having hoary leaves

Other synonyms of blue sage include Artemisia tridentata, Seriphidium tridentatum.

blue sage (noun)	big sagebrush (noun)
aromatic shrub of arid regions of western North America having hoary leaves	aromatic shrub of arid regions of western North America having hoary leaves
blue-flowered sage of dry prairies of the eastern United States
Texas sage having intensely blue flowers
sage of western North America to Central America having violet-blue flowers; widespread in cultivation