sweet pepperbush vs pepper bush

sweet pepperbush and pepper bush both are nouns.

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

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

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

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

sweet pepperbush (noun)	pepper bush (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