Welcome to the forum Julia. The b/w rose looks the only good shoot among all. Actually it is more than good, very very good. The other 3 have composition issues. I remember we had few very good photographers shooting flowers here on the forum. Look up their work.
Welcome aboard. I agree with the previous comments, the B&W rose is a great photo. The others don't do much for me.
Yes...B&W is the best,,,violet would have been lovely if the flowers were fully within the frame...the remaining two are compositional problems as already been pointed out' O, forgot...Hearty Welcome