The bush belongs to my parents in central Illinois. They've had no soil test done and I'm sure they won't be doing one any time soon, so we're working from some limitations.

They mentioned to me that they have this bush and it is supposed to turn bright red in the fall, but hasn't been. They contacted the extension service at U of I and were told to apply copper sulfate at a certain rate three times a year (of course the exact rate and dates of application are only available once they get home and they'll probably forget they're supposed to tell me).

They did tell me that some kind of landscaping fabric was used to suppress weeds and they can't let the leaves stay there and return the nutrients to the same area.

They said the leaves are turning redder now than before, but not as red as they should. I googled and discovered that insufficient sunlight is often a cause and was assured that it gets sufficient light.

I then asked where they put the copper sulfate and they told me that they put it down right next to the trunk and then outward a little ways, almost to the drip line, but most heavily right next to the trunk. I know that with trees, you'd want to go in an area from the dripline extending a little ways out and in, but not near the trunk. I'd assume it would be the same for a bush, but I don't know for sure. Does anybody know?

Also, can copper sulfate be applied as a foliar spray?

They could have been fertilized too late in the season, which causes new growth and that sometimes makes them not turn red. As you know Sun has alot to do with it as well. Also if it is not cold enough outside. Are there any maple trees around it? If they are turning red then the bush should be as well

They have a red maple, but it has red leaves all the time, so I don' think that's what you mean.

They used to have a silver maple, but it has been gone for 20 years or so and I don't remember whether it ever had red leaves in the fall.

Just a regular old maple with green leaves in the summer and then they turen red or orange in the fall. Trees are just starting to turn red around here. What has you temps been? Sorry i don't have a answer for your copper question.

I should have been more clear.

They talked with the extension service several years ago and this was the third year (or maybe the 4th) they applied the copper sulfate. So when they told me that it hasn't been as red as they'd like, they're basing it on how red it has turned the past few years after applying the copper sulfate. I think they mentioned it after we were talking about the colors in the mountains.

I doubt if any of the leaves in central IL have started turning color yet.

They weren't really asking me for help with this; they just sort of mentioned it offhand. I don't have any experience with that bush (or really bushes in general) but I know that when I apply iron chelate to my maple, I put it out around the dripline so I thought the same principle might apply and that they'd get better results applying it around the dripline than next to the trunk. And if there's something interfering with copper uptake, a foliar spray (even a light one) might help.

I asked about the sun and they said it gets plenty of sun. I don't know what "plenty" means, but they assured me that it's in full sun.