winter heath vs erica

winter heath and erica both are nouns.

Word	Noun	Adjective	Verb	Adverb
winter heath	Yes	No	No	No
erica	Yes	No	No	No

As nouns, erica is a hypernym of winter heath; that is, erica is a word with a broader meaning than winter heath:

winter heath: dwarf European shrub with very early blooming bell-shaped red flowers
erica: any plant of the genus Erica

Other hypernyms of winter heath include true heath.

winter heath (noun)	erica (noun)
dwarf European shrub with very early blooming bell-shaped red flowers	any plant of the genus Erica