garland vs bay wreath

garland and bay wreath both are nouns.

Word	Noun	Adjective	Verb	Adverb
garland	Yes	No	Yes	No
bay wreath	Yes	No	No	No

As nouns, bay wreath is a hyponym of garland; that is, bay wreath is a word with a more specific, narrower meaning than garland:

garland: flower arrangement consisting of a circular band of foliage or flowers for ornamental purposes
bay wreath: (antiquity) a wreath of laurel foliage worn on the head as an emblem of victory

Other hyponyms of garland include crown, laurel, laurel wreath.

garland (noun)	bay wreath (noun)
flower arrangement consisting of a circular band of foliage or flowers for ornamental purposes	(antiquity) a wreath of laurel foliage worn on the head as an emblem of victory
an anthology of short literary pieces and poems and ballads etc.

garland (verb)	bay wreath (verb)
adorn with bands of flowers or leaves