Oh me too. My city does these flower towers a lot and they typically feature petunias in all the colours. Afaik it should be fairly doable.
Petunia is the one I've always been most succesfull with, seems it just needs the sun and pinching out the spent flowers. Grew a huge pink one in a hanging basket one year, it got massive. Absolute joy. It was also one of these layered varietes like the ones I am growing this year, these are my favourites for sure. The seed mix I got this year is mixed colour and so far I have this light purple one, deep pink, dark purple and one that is sort of light red.
