"Has the flower bloomed?"
I really think this should be さいてますかor さいたことがあいますか. But that's just me. Or make the english "did the flower bloom". Or something
First one would be さいています and would mean "currently blooming..." I guess it could work but not exactly the same. さいたことがあります would be more like asking if it has bloomed in the past. Sounds kinda odd.. Like a tree that only blooms every few years or something.
Since it says "the flower" (definite article), should it be が instead of は? Using "the" makes it sound like the flower is already been talked about i.e. not a new topic. I know there's no 1-2-1 equivalent of articles in Japanese and I'm probably misunderstanding は・が but I thought it might be worth asking.
ha is the topic you're talking about and ga is the subject. Hope that helps :)
Which is why it should be also right to use ga here, since the flower is the one being emphasized to bloom. Even if the implied topic is the speaker (in most japanese sentences), the context of this particular question statement won't change the literal translation. It won't make sense to imply the speaker here.
I think the word for blooom is さき, and your sentence sound correct, if anyone could further explain the difference?