My first thought is spider mites causing the mottled leaves. Are you in the UK? Here they get them quite readily, especially if stressed or if grown in sun. A regular forceful spraying with a water hose should blast off most of them.

funnily enough, when I was picking up the dropped leaves there was a very small spider on one of the leaves. Yes, in the UK. I'll do your suggestion and look up spider mites online. Thanks!

Tina, if the plant in the picture with berries is yours it isn't 'Rubella'. Skimmias have male and female flowers on different plants. 'Rubella' is a male cultivar grown for its red buds and scented flowers, so it won't produce berries. Unless, of course, there are two different cultivars in the pot to ensure berries. When you repotted did you find two separate plants?

I would get the plant out from under the porch. Rain is a good aid against spidermites. They prefer warm dry conditions.

Now you've covered the drainage and soil issues I'd just leave it in peace for a while and give it time to recover. Review come next spring.

Ah! I could be wrong about naming the plant! It has red berries and in spring it had little white flowers. I'll find a new home for them. Thanks for your help, bugs were the last thing I thought of! Would it help if I sprayed the leaves with soapy water or is that just for aphids?

There is definitely a mite issue going on - the bottom leaf in the top photo has classic skimmia mite damage. As Dave indicated, mite infestation on skimmia are very common on plants that receive too much sun or are otherwise stressed. But I'll let floral suggest how to care for your plant - she is far more familiar with your growing conditions than I am :-))

Thank you gardengal

Tina - there are lots of cultivars of Skimmia japonica. If yours has berries then it is one of the female cultivars.

The spidermites may be due to stress from the erratic watering and the lack of natural weather under the porch. As I suggested above, now you've addressed the acidity and drainage issues I'd get it out from the shelter into the weather and leave it in peace for a good few weeks. Unless your front door faces south I doubt it will get too much sun.

Thank you. It just started to rain so I've put it out in the open again :)

Looks like the larger leaved, large-growing, self-fertile kind I've seen labeled Skimmia reevesiana at the Seattle arboretum. (I thought I used to see this particular version called S. japonica 'Macrophylla' elsewhere but have found little, if any validation of that name when looking in later years). Skimmia are full shade plants, mites - which this has - or not the leaves will never be attractive if the plant keeps being placed in sunny aspects.

Mites of this type are tiny specks it may take a magnifier to see well. The animal you saw was probably a spider instead.

Thanks. Looks like I had the shade it needed on the porch but I had no idea about mites. It's still dropping leaves, even the small new ones.

Full shade in the British Isles can be very dark. These things manage fine in semi or dappled shade. In deep shade they can get leggy. I would still recommend not keeping it under the porch.

Dark is what this wants. On Camano Island I'm growing skimmias under Leyland cypresses. Along with Aucuba and Sarcococca. Portugal laurels come up from seed in the same situation and are able to develop.

Shrubs which want deep shade with moderate moisture....include:

...Skimmia, all species and vars....

--John A. Grant and Carol L. Grant, Garden Design Illustrated

This time I am going to dig my heels in, Embo. These things are common as muck over here and they do not need deep shade. Partial, yes. Dappled, yes. They can take deep shade but they don't require it. I had several in a previous garden in a bosky situation. But it was not deep shade. The usual problem is chlorosis from our predominantly alkaline soils.

We don't know the light conditions in the OP's situation. But I still think it is important to get this thing out from the porch and into natural weather as long as it isn't an excessively sunny aspect.

You're right about alkaline soil! I'm from North Kent, chalky soul is common! There is no direct sun out the front, it's north facing, but it is light. They're still off the porch so they'll catch any rain water. The weather is weird, if it rains it's been torrential, but mostly dry and warm. It's probably a mix of all kinds of stresses - the mites, not having suitable soil for so many months, having tap water not rain water. It's berries and flowers were beautiful! It's just this last month. I'm removing the damaged leaves and hoping for the best. Thank you all for your advice, you're all clearly much more knowledgable plant lovers than myself.

Tina, that sounds like perfect spot for them. They should improve now you've got them in ericaceous compost. The exposure to rain doesn't mean they won't need watering. But I am a great believer in weather for helping to keep pests at bay. Spidermites like it warm and dry.

So here's the sorry state of my Japonica 10 days on from my first post. I've been removing the dropping leaves (those shown on the ground are from the last 24hrs), I've been squirting with soapy water while waiting for a spider mite organic spray to arrive in the post, and not letting the compost dry out (I feel down a little way to check). The remaining leaves feel less grainy under my finger and thumb so maybe I've removed some spider mites but I fear it's too late! There are however lots of new shoots, though the baby leaves come away too. I'm guessing I shouldn't remove the remaining leaves otherwise there'll be no photosynthesis. Persevere until my organic spray comes (hopefully today) and use that to spray the buds?

Tina have you found a solution as I belive to be in similar state