large-flowering magnolia vs southern magnolia

large-flowering magnolia and southern magnolia both are nouns.

Word	Noun	Adjective	Verb	Adverb
large-flowering magnolia	Yes	No	No	No
southern magnolia	Yes	No	No	No

As nouns, large-flowering magnolia and southern magnolia are synonyms defined as:

large-flowering magnolia and southern magnolia: evergreen tree of southern United States having large stiff glossy leaves and huge white sweet-smelling flowers

Other synonyms of large-flowering magnolia include bull bay, evergreen magnolia, Magnolia grandiflora.

large-flowering magnolia (noun)	southern magnolia (noun)
evergreen tree of southern United States having large stiff glossy leaves and huge white sweet-smelling flowers	evergreen tree of southern United States having large stiff glossy leaves and huge white sweet-smelling flowers