HELP

I need help right away. I live in Montana so just planted my garden last week. The nightmare started yesterday. I noticed my marigold leaves were turning a silver/white color. I didn't pay much attention because the blossoms looked healthy. Today I found that this silver white has spread to my salvia, snapdragons and even to some of my perennials. I need help desperately to stop this.

I pulled all of the marigolds (at least 3 dozen) and removed leaves from other plants that were showing the same silvey white. It is not powdery mildew because it doesn's rub off. It's a very shinny silver look.

Please, please, can anybody help me?

It sounds like sun scald, did you just buy these plants and plant them without any hardening off process? Often plants that are grown inside greenhouse conditions need a gradual period of being introduced to full sun conditions. Even though it is hot in the greenhouse, hot sun and wind can really stress new plants.
If this is the case could you put some light row cover fabric over them to acclimate them gradually?

All of the plants had been in the greenhouse up until about a week ago. They did fine for the first 5 or 6 days. Sun scald makes sense because we haven't had a bit of sunshine here until today. The sun was blazing hot all day. I really hope that's all it is and that everything recovers. Thanks so much for your help. I couldn't find anything on line that fit what was happening so I was really stressing out. Just before dark, in a panic, I pulled all my marigolds and cut the damaged leaves off of all the plants thinking I had something really catchy.

Montana is a tough place to grow anything. It gets so cold at night (not freezing or frost) and when, and if, summer ever gets here it will be a scorcher. Thanks again.

Hope that helps, I couldn't see any other thing it could be. And I thought it was tough gardening in Minnesota! Happy gardening in spite of it.