periwinkle vs suffrutex

periwinkle and suffrutex both are nouns.

Word	Noun	Adjective	Verb	Adverb
periwinkle	Yes	No	No	No
suffrutex	Yes	No	No	No

As nouns, suffrutex is a hypernym of periwinkle; that is, suffrutex is a word with a broader meaning than periwinkle:

Other hypernyms of periwinkle include subshrub.

periwinkle (noun)	suffrutex (noun)
edible marine gastropod	low-growing woody shrub or perennial with woody base
small edible marine snail; steamed in wine or baked
chiefly trailing poisonous plants with blue flowers
commonly cultivated Old World woody herb having large pinkish to red flowers