"Pe câmpie sunt multe flori galbene."

Translation: On the plain there are many yellow flowers.

[FaizalZahid]

Is 'field' considered wrong?

[Lurch_M]

Yep, it's wrong. See this thread to find out why.

[Pop60]

On the plain are many yellow flowers.
I can imagine this as being written in a book, maybe said by someone giving a lecture.... There is an optional word, not wrong, but not a direct translation from the Romanian, and not unequivocally necessary in the English.