Star Jasmine with red leaves???

Hi all.. been in the garden for the first time in ages and been sorting plants.. plants & acers looking dead due to to vine weevil but the most confusing is my star jasmine.. its leaves turned red over winter and are still red?!  What can cause this?

Winter cold will do it. It happens to mine. Give it time and some warmth and things will right themselves.

Its been cold indeed, leaves get red like our poor noses do in the cold!  New leaves will be normal if it ever gets warm enough ...............

I started a thread earlier in the year on my Star Jasmine problems with not producing new growth or leaves going yellow etc.  Since then it's put on new leaves in the last three weeks which are light new green coloured but some of the older leaves are rapidly turning a variety of colours from yellow to orange to brown. 

I'm now wondering if it's to do with the 'summer mulch' I put down a month or so ago as since then things like Hebe, Roses sprung into life but the foliage on the Star Jasmine, Geraniums 'Mrs Kendall Clark' have all turned browney orange and yellow.  My Geraniums promptly stopped blooming and I had expected them to bloom for quite a while yet.  The mulch has calcified seaweed in it but don't know what else.  Bought it from a really good nursery - but maybe I've carelessly had it too near the plant stems.  Not sure if that's what the problem is. 

Jasmines will always drop their old leaves in my experience. Red leaves at this time of year can mean overwatering. We've had stinking hot weather for months, I was pouring water on the jasmine, with red leaves the result. I laid off the water and they disappeared.