I have a green roof covered with sedum plants and I noticed that in the late spring and summer many sedum plants turn red. The same plants placed in our garden (in the shade) stay green all summer. I suspect the cause of the sedum turning red is either a lack of nutrition (fertilizer?) or water.
The red sedum does survive but I'm worried that it may cause problems in the long run. Can sedum turning red every summer become a problem, and if so what can I do about it?