Does that pot have drainage holes? Is it planted in reasonably draining soil?

And does it sit in full sun? The black worries me about heat.

The plant is actually in a pot within that pot and both have drainage holes. It was in a very shady spot getting only a few hours of early morning sun. That was until about 2-3 weeks ago when I moved it to where it is in the photo where it gets more sun than before but still morning sun. The house provides shade for it the rest of the day.

It looks no better and no worse since I moved it.

Maybe root bound?

Would it be okay to repot this in Al's 511 mix?

If it IS indeed rootbound, do I trim the roots??

Honestly I think it would be best suited in the ground. In a big enough container it would probably do well in the 5-1-1 mix, but that mix is really only meant to be used one season and discarded. I'm not sure about pruning the roots either, hopefully someone with more experience will chime in.

Pieris shrubs grow and flower best when planted in full sun or partial sun and shade. They will grow in full shade, but generally do not flower as well and the new foliage growth is usually not as brilliant. Be sure to provide good drainage for the plants. The soil in which they are grown should contain a high content of organic humus. This can be added at planting time, in the form of peat moss, compost or processed (bagged well-rotted) manure. I wood try re potting if it were mine and fast

Well it's definitely not from either over fertilizing or over watering since I have never fertilized it, and since I was watering only 1x every 2-3 weeks per advice from someone who obviously had no idea what they were talking about.

It was also getting very little morning sun which may have contributed as well. Could little sun, little water, and no fertilizing cause this? Lol. I feel like I answered my own question. What I really want to know is what plan of action to take in helping the poor hung recover.

I'm scared to root prune as I've never done it before. Should I only prune off rotted roots(what are these distinguished by?) and circling roots? Or should I do an overall trim? Should I take off the brown leaves or let them fall on their own?

Thanks!

You've almost convinced me that it might be under-watering, which is the least of the evils. It's unlikely your plant would simply collapse from too much sun, unless it had been in deep shade for a prolonged stay before you got it, and I can see it wasn't.

I can't determine how dry the plant got from here, but it doesn't like to dry down completely. If it did, then chalk it up to grower error and start keeping the plant evenly moist. Hopefully it will bounce back, but it might take a while and you might have to remove a lot of dead stuff eventually. Partially burying the pot and watering often is a good plan, as long as the spot where you sited the pot is well-drained.

Best luck!

Al