Well, maja, I think that this plant would have been identifed for you by now, if possible. You might have a better chance if you go to the Florida forum, post the location and a good description. You just might run into someone who knows exactly what you are talking about.

BTW, try not to mention that it 'looks like a petunia' unless it actually does. We humans are very prone to suggestion....and are likely to think of nothing but petunias!!!! (Of course, if it DOES look a whole lot like a petunia, stick to your guns!)

It occured to me that you might have seen a purple 'Million Bells', or Calibrachoa. There is one hybrid 'super bells' which is dark purple.

This is also a plant that IS related to the petunia!!!

Here is a link that might be useful:

Just a wild guess.....Mexican Petunias......I have them and they are very hardy. Descriptions sounds like what I have.