In my part of NC ( on the cusp of zones 7 and 8) petunias self seed vigorously, to the point of being invasive, and even manage to overwinter. The ones that do are older heirloom varieties that have been self propigating here for over well 50 years so I have no idea what the original stock was. Obviously they are well adapted to the heat and humidity but the blooms take on more muted colors like white or pale pink. They get quite leggy but, having just found out the benefits of pruning them, this year I will try to keep them to a better form.
I grow the F1 types in baskets and have found that by doing this cross pollination occurs with the older types giving them much deeper colors, fuscia to purple, and patterns. They're a real box of chocolates.
[lightbox]2018-03-09/UncleWill
