gentiana failing

I have a gentiana hybrid "shot silk" which I planted last autumn and has steadily deteriated ever since. At the moment it is in a pot and has a small flicker of green on it (by which I mean that there is a small flicker of green at soil level to show where the plant is!). It was in a south east facing rockery. The soil is neutral to alkaline but I dug out an especially wide area and filled it with peat and sulphate of Iron was added to lower the ph as I understand it is quite acid loving. Any other ideas before it flickers out completely?

 

It is hungry. The best substrata for Shot silk is a great big Yak dropping. Failing that try planting it on a nice dollop of cow muck. Or you could feed it from now on with Tomorite.

 

Thanks for that. I'll source out some bovine country pancakes, shame cat poo doesn't have the same effect.