Answer: All three of these require a well drained location. With a heavy clay soil, the best planting site would be on a slight slope which would allow excess runoff to drain away. You would also have to be careful not to plant your shrubs too deeply. In overly wet soil or if planted too deep they will suffer root damage and will die back and/o possibly die as a result. Without seeing the plant it is difficult to say whether or not you are seeing a seasonal change, a response to changed light levels, or something else. I would strongly suggest you consult with the retailer where you purchased the plants, especially if there is a warranty involved. Good luck with your shrubs!
Q&A Library Searching Tips