That isn't a Rhododendron it is a Hydrangea... I know tho is going off at a tangent to your actual question but there doesn't seem to be an awful lot of soil in the pot and it looks very wet. Does the pot have drainage and is it stood on feet to keep it off the ground? Are you sure the damage is being done by snails, or, in other words are you actually seeing snails on the shrub.

Oh.gosh,it is how stupid of me.
I haven`t seen any snails in the pot or on the plant.It was a cutting I got from a neighbours bush,which I got late last year,it then "disappeared",come winter and I thought that that was it...gone!
Lo and behold,come Spring and it is now growing lovely and don`t want the pesky snails spoiling it.
Have put slug pellets around the base of the pot and that did kill off a few.But does`t look very nice having the pellets there as they are blue.
Thank you for replying.Have a nice day.

You don' t need many pellets Solada - three or four would be plenty and you can place them so they are out of sight - slugs and snails will hunt them out if they are there.

Agree with MG there isn't much compost in that pot so in the autumn you might upend the pot carefully and fill the bottom with fresh compost, replace the plant and top up round the edges with new compost too. Hope this makes sense. It looks very healthy at present but if roots start to appear in the drainage holes during the summer you could risk doing it then, as long as you don't disturb the roots.

Does anybody know if copper repels Snails and slugs or is that a myth? Thanks

I have a copper band around the above plant but it still got holes in it...so Stera,is it that slugs like the pellets,the smell whatever and go for them?
I have put loads of pellets and it has killed a few...but I am sure they have still been feeding off my plant,checked the soil in pot and cannot find any .It was growing lovely and now look at it!!!!

Thank you all for replying.

They certainly do seem to like the pellets Solada! I'm not convinced those little holes are slug damage though. It could be something else entirely. Have you examined the back of the leaves to see if there are any small insects there? I really wouldn't worry too much about it unless it gets a lot worse. It is still growing very well and looks very healthy - it even has a flower bud although its such a young one. We can't expect total perfection in our outdoor plants. Looks to me as though you are doing everything right apart from MG's comments about the soil level.
Also re the pellets - its usual to put a few in the pot rather than round it - the copper band should stop them entering from the ground.

Hi Stera,I have checked the leaves and cannot see anything there.I did wonder if one can put pellets in the pot instead of round it.Thought it night harm the soil,you may have noticed I have wood chipping on the top of it,that OK?
I am a very amateur gardener ...as you have probably realised by now.
Thank you so much for your advice.

Pellets won't harm the compost or the plant. If the wood chippings are well rotted they'll be fine but if not there is the possibility of some drawbacks as they do rot down. (Little toadstools, harmless but not everyone likes them, and perhaps some nitrogen depletion.) If you want to repel slugs coarse grit would be more effective as they are reluctant to crawl over it.. You could perhaps change them when you repot the plant as advised.

Thank you very much?