Q.Will Too Much Bordox Harm My Peach Tree?
I accidentally sprayed my peach tree with a very concentrated Bordeaux mix and the trunk os blue. When I realized how strong the mix was I stopped and watered it down. Will this harm the tree? It is a mature tree, not sure how old, as we just bought the house last year. I did this yesterday, and the tree shows very small buds and some red growth. The blue is on the lower part of the trunk, but I may have still had the mix a little strong because the rest of the tree has a bluish tint.

Certified GKH Gardening Expert
You did the right thing in spraying down the tree with water. Hopefully your action was quick enough because the mixture can be corrosive. It wouldn’t hurt to spray it down again with water. The blue color is expected, so that is OK. If the tree seems normal you should spray again in 2 weeks. If it seems affected by first spray, skip the second application.
Here is more:
https://www.gardeningknowhow.com/edible/fruits/peach/spraying-peach-trees.htm
https://www.gardeningknowhow.com/garden-how-to/info/diy-bordeaux-fungicide.htm