Sure, but hoznak is present tense.
And I think they're trying to use a plural verb form "bring" there, but it sounds unnatural to me - "Who brings flowers?" or "Who is bringing flowers?" is what I would say, even if the answer may be "John and Susie" (i.e. multiple people).
The closest I would get to an explicit plural question would be "Who all is bringing flowers?" with "who all", but even then, I would use a singular verb.
(Similarly in German, for what it's worth: Wer bringt alles Blumen?)