Why do the green leaves on our petunias turn to a real light green?

Question:The petunias seem to be thriving and have a lot of flowers and buds. Some are planted in the ground and some are in hanging planters. We use a 10-50-10 fertilizer. We have many other types of annuals and don't have the same problem. Also, I think the petals of the petunias are faded somewhat.

Answers:
mmmmmm,
I would suspect too much water or not enough sun
petunias do better with a little water each morning. at least mine did,but then I had mine in a circle and in direct sunlight . They were always healthy green Are they getting enough sun? and of course they will fade if they are "done" just pluck the light green ones off it might just be part of the pruning you need to do for your area. Petunias are pretty resilient unless you have 3 boys and 3 dogs :( lol