Why did the speaker say “バラの花を貰った” instead of just “バラを貰った”?

Question

Here is a conversation excerpt:

(娘) 初めて貰った花束がお別れの花束なんて悲しい。
(母)この前の誕生日にバラの花を貰ったでしょう。

"バラの花" seems redundant to me. There is no reason to state that a rose is a flower. Does

(母)この前の誕生日にバラを貰ったでしょう。

also sound natural?

If "...バラを貰った..." does not sound natural, then my conjecture:
(-) "バラの花束" definitely means more than one rose.
(-) Maybe does "バラの花" explicitly means just one rose?
(-) And, "バラ" by itself could mean one, or many, roses?

note: That the daughter had initially received just one rose last year, instead of a bouquet, was central to the larger discussion that they were having.

Answer 1

誕生日にバラの花を貰った and 誕生日にバラを貰った are both natural, and people usually imagine exactly the same thing. Both can mean ether one rose or or a bouquet. In this sense, yes, ～の花 is redundant.

But many people add ～の花 anyway. It's hard to logically explain why, but perhaps it's just because it's a very common and nice way of putting it. We see バラの花 in ads, lyrics and everywhere, and virtually no one wonders if it's unnecessarily long.

Answer 2

バラ can refer to the rosebush, not just the rose. The term developed from older form 茨{うばら}, which referred generally to brambles and other thorny shrubs.