Last September I bought a gardenia that I potted in a 5 litre container using, by the sales guy, recommended ericaceous pot soil.
It has looked quite healthy all winter, although obviously it hasn't grown anything.
About four weeks ago, after checking the soil and seeing that the bagged soil was way too soggy and that the plant hasn't grown any new roots (the old roots was still in good shape, white and healthy) I decided to repot it into a mix comprised of 5 parts pine bark fines, 1 part DE and 1 part perlite. Since then the leaves has gradually lost their nice dark green colour and lately started to look dried up. It hasn't lost any leaves yet. I have watered it only when all of the mix has started to dry up, using a wick to drain it of any perched water every time. The first week I kept it in the shade all day and then gradually moved it into morning sun/afternoon shade and that's where I kept it since.
I dug gently today into the mix to examine the roots and they still look white and healthy but haven't grown much new since the repot.
When I repotted I gently shook off the outer layers of the old mix and bare rooted it in two wedges being about half of the old mix. Both in the old mix as in the new the (old) roots looks healthy.
As a pre-caution I today put the plant in a plastic bag (the soil is just slightly damp and not wet) to maybe help it stop drying up more.
I have fertilised once (last weekend) with FP 9-3-6 and some citiric acid added to my tap water (which I add every time I water).
Does anyone have any ideas as to what the problem might be? Is it a good thing to keep it in the plastic bag tent or not?
I will post a photo tomorrow when I have some light (already late in the UK).

Thanks very much in advance.

.johan

Mike