Erica carnea vs true heath

Erica carnea and true heath both are nouns.

Word	Noun	Adjective	Verb	Adverb
Erica carnea	Yes	No	No	No
true heath	Yes	No	No	No

As nouns, true heath is a hypernym of Erica carnea; that is, true heath is a word with a broader meaning than Erica carnea:

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

Other hypernyms of Erica carnea include erica.

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