Privyet comrade.

Have you studied the history and philosophy of Constructivism in photography and art in general.

I would say subject matter DOES REALLY MATTER but more importantly it is how the subjects are portrayed, arranged, lit and in some cases deconstructed and then assembled in a fractured manner. ( on first thought, flowers would not seem to be a good subject to reflect modern industrial society but perhaps your artistic vision will find a way to turn then into a statement. )

Photomontage was a big part of Constructivism photographic art. Constructivist artists made use of "jagged angles, contrasts and abstract use of light". ( Quote from the Constructivism Wikipedia )

Constructivist art was born from a passion of broader social and political ideology, and i would suggest that if you want to create Constructivist art that you should also Understand that ideology and be passionate about why you want to use Constructivist art. That requires a deep understanding of what it is, why it came to be, how it was used and what it was trying to say and what you want to say.

An artist should create from a passion and a vision that is deep within themselves, we can not give you that passion or vision. If photography is the tool you want to communicate Constructivism ideology then you should have a deep knowledge of Constructivism and why it exists.

If you are not passionate about Constructivism ideology per-say but just love the art born from it and its aesthetic beauty then i would suggest that you still need to understand it's history and how it was created, and used, in order to create your own Constructivist style art.