My petunias are developing malformed in one of my 7 planters. The plants aren't loosing leaves and it appears to only affect the flowers. I had this problem late in the summer last year and a local master gardener told me it was just because they were done blooming for the season. Since they are doing it again, I think it's safe to say thats not the issue. The dianthus, bacopa and Dusty Miller in the pot seem fine. The Nicotainia also looks to be suffering the same condition as the petunias. The planter is a whiskey barrel. Any suggestions?