Question
The blossoms that make it to opening are wilted looking with white or black on the edges of the petals & they fade
immediately.  I checked the tiny tiny buds & they are brown & rotten looking.  I could not find any bugs or caterpillars on them.  The plants themselves look healthy
enough - it's just a problem with the flowers.  Could this
be a fungus of some sort?  I had petunias in this location
last year & by deadheading every couple of days they bushed
out & bloomed spendidly all summer long.  They get plenty of sun & have good drianage.

Answer
Debbie,
It could be a fungal problem but usually the cause of such fungal problems is that the flowers are getting wet, either by rain, mist or when you water. Petunia flowers look awful when they get wet. You can't do anything about the weather, but when you water try not to get the flowers wet - stick the watering can or hose under the plants and water low down - also water early in the morning so if the flowers do get wet they dry off quickly.

I hope this helps,
C.L.