go out after dark.. and see if the white rock is still hot ... is there landscape fabric under the stone???

if its not rock.. nevermind .. lol ...

plants need a cool overnight relief period.. to recover from the onslaught of the day ... when we add things that retain the heat.. we interfere with that .. and possibly stress the plants ...

otherwise.. how about a pic of the whole plant.. how big are they.. how did you plant them.. and how do you water them ...

ken

Hey Ken! There’s landscaping fabric under the marble chunks. They’re still fairly small and I planted them prior to laying the fabric around them and adding the rocks. We have a sprinkler system that is on every other day and lately I’ve been watering them twice a week since I noticed the red. There are two closer to the house which get shade from our porch, so it may be the retained heat from the rocks. I’ll go check tonight. If so, Is there any solution other than removing the rocks- I really would hate to do that. I’ve added a few other photos.

The two closer to the house that get shade do not show the same reddening on the outside of leaves...

It’s my opinion that rock (or marble chips) for mulch is always a bad idea. They retain heat and cook the plants.