It's good having a south-facing garden but the sun can take its toll on materials exposed to it.
I have a small area (about 3sqm) of timber shiplap cladding that has seen better days (peeling paint and weathered wood) and would be simpler to replace [1] than refurbish. Replacing like for like would give the same problem in a few years. The question is, what would be the best material for a 'fit and forget' solution? Thoughts so far include: Varnished hardwood - would still deteriorate in time uPVC shilap - shiny white wouldn't look good and creaks nadtily when it expands in the sun, but I can't see any sensible info on how well the darker foil-faced versions last. Fibre cement cladding - plenty of finishes available but seems to be painted, not coloured throughout the thickness, so would possibly give the same problem again. Bricks - a lot of faffing to do, given the location, and I'm struggling to source bricks that match the house for other purposes. Synthetic slates - should be pretty sun-resistant but may be challenging to hang vertically.
In the US, they use aluminium 'siding' that lasts well, provided it doesn't suffer any impact damage. I've never seen it in the UK.
[1] As I'm in a conservation area, I really shouldn't have any sort of cladding anywhere, apparently (wtf is that rule about?), but I don't think anyone will notice on a like-for-like replacement at the back of the house.