trachleospermum leaf spots

Pippa7

Dear Gardeners
Please could someone help identify the cause of this evergreen jasmine leaf spot
I've just noticed it. new plant last year. main worry is to be sure its not contagious as I have a beautiful mature plant right next to it that I wouldn't want contaminated. but if its just nutritional etc then wouldn't want to chop this one down for no reason. 
Kind regards. keep well
Thank you P x 

Pete.8

Is it one leaf or the whole plant that's affected?
The odd leaf with some marks unlikely to be anything to worry about, if there's a lot of them that may warrant further investigation
If you have a magnifying glass see if you can see any bugs on the underside of affected leaves.

Pippa7

Thanks for your interest Pete
under the magnifying glass there was only a very fine dust which could be a red herring, nothing actually moving around 
approx 10% of the leaves are affected 
here are a few more examples 

Pete.8

It's nothing that I recognise Pippa and I would imagine that it's just one of those things and your plant will grow out of it.
It may well be a deficiency of some trace minerals so it would be a good idea to give it good mulch with rotted compost at this time of year and make sure it doesn't dry out in the warmer months. Alternatively, a good drench with seaweed extract will ensure all the trace minerals are available.
If your plant is otherwise healthy see how it goes once it starts growing again.
I had 3 of these (all now lost due to building works..) and the leaves do take a bit of a battering over winter.
I'm sure if any one else here recognises it they will post.

I did find this thread - but there wasn't a resolution
https://forum.gardenersworld.com/discussion/2378/star-jasmine-trachelospermum-jasminoides/p1

Pippa7

Thank you very much Pete. I have clay soil so maybe it’s the root rot trouble. I will certainly try your suggestions