Flowers real - but colours articicial

I was at Buenos Aires, Argentina in 2007.  There I happened to visit a small fair or carnival type of event.  Here persons from various trades had set their shops and were displaying there wares for sale.  Among there, there was also a florist selling flowers.

     Here I was a baffled because one of the flowers he was selling are only white.  But he had these in several colours. I discovered that these colours were not natural.  In fact what he had done, was the flowers were dipped in coloured water overnight. They had picked up the coloured water and changed their colour.  Here is a picture of those fowers?

 

      What would you call this.  Is it not floricultural adulteration?  Please do write me.