spring heath vs erica

spring heath and erica both are nouns.

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

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

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

Other hypernyms of spring heath include true heath.

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