pepper bush vs sweet pepperbush

pepper bush and sweet pepperbush both are nouns.

Word	Noun	Adjective	Verb	Adverb
pepper bush	Yes	No	No	No
sweet pepperbush	Yes	No	No	No

As nouns, pepper bush and sweet pepperbush are synonyms defined as:

pepper bush and sweet pepperbush: shrub of eastern and southern coastal United States having beautiful racemes of spice-scented white flowers

Other synonyms of pepper bush include Clethra alnifolia, summer sweet, white alder.

pepper bush (noun)	sweet pepperbush (noun)
shrub of eastern and southern coastal United States having beautiful racemes of spice-scented white flowers	shrub of eastern and southern coastal United States having beautiful racemes of spice-scented white flowers