Q.Clematis princess diana
I ourchased a very healthy looking plant from a reputable siyrse, but after six weeks it appears to be dying. It has been watered well, is placed in a sunny but sheltered position but obviously doesn’t like something about its environment. I planted it in a hole which had been well prepared with a mixture of potting compost, John nines and a little bagged farm yard manure, as my soil is extremely sandy. What dud I do wrong?
Well draining soil is important. Make sure the soil is moist but not soggy.
This link will help you review the care needed.
https://www.gardeningknowhow.com/ornamental/vines/clematis/growing-clematis.htm