Bartram Juneberry vs shadbush

Bartram Juneberry and shadbush both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bartram Juneberry	Yes	No	No	No
shadbush	Yes	No	No	No

As nouns, shadbush is a hypernym of Bartram Juneberry; that is, shadbush is a word with a broader meaning than Bartram Juneberry:

Bartram Juneberry: open-growing shrub of eastern North America having pure white flowers and small waxy almost black fruits
shadbush: any of various North American trees or shrubs having showy white flowers and edible blue-black or purplish fruit

Other hypernyms of Bartram Juneberry include Juneberry, service tree, serviceberry, shadblow.

Bartram Juneberry (noun)	shadbush (noun)
open-growing shrub of eastern North America having pure white flowers and small waxy almost black fruits	any of various North American trees or shrubs having showy white flowers and edible blue-black or purplish fruit