This spring my landscapers planted 4 vine maples, (about 5 feet tall), three on a hillside that gets direct sun only for 2-3 hours in summer. The problem one is in sun for maybe 6-7 hours a day. Also, it appears to be in a higher-than-normal clayish soil (more soil than clay, but clearly the reddish color is visible in the soil). One of the vines has leaves turning red, more so the farther out and up you go. But the leaves are all green-yellow, compared to the three in the soft very good soil and shade which are all dark green to the tops.

When I first saw the problem over a month ago, I increased the water, but that made no difference. Slowly the leaves continue to redden.

Is my problem too much sun? Too much clay in the soil? Too much worry on my part?