Bed of flowers and Rose bed

Bed of flowers noun - A bed in which flowers are growing.

Rose bed and bed of flowers are semantically related. In some cases you can replace phrase "Rose bed" with "Bed of flowers", this phrases are similar.

Rose bed noun - A flower bed in which roses are growing.

Bed of flowers and rose bed are semantically related. You can use "Bed of flowers" instead a noun phrase "Rose bed".