flowerbed vs bed of flowers

flowerbed and bed of flowers both are nouns.

Word	Noun	Adjective	Verb	Adverb
flowerbed	Yes	No	No	No
bed of flowers	Yes	No	No	No

As nouns, flowerbed and bed of flowers are synonyms defined as:

Other synonyms of flowerbed include flower bed.

flowerbed (noun)	bed of flowers (noun)
a bed in which flowers are growing	a bed in which flowers are growing