Hi @ash15cooper,
It looks like this is a Photinia serratifolia, commonly called Japanese, Chinese or Taiwanese Photinia.
It looks like it is suffering from Photinia leaf spot which is a common fungal disease that affects photinias. It shows up as dark red to purple spots on the leaves, and can cause leaves to yellow and drop if the infection is heavy. Over time this weakens the plant and makes it look thin and stressed.
The disease is caused by a fungus that thrives in warm, humid conditions. It spreads through water splash from rain or overhead watering and overwinters on infected leaves, both on the plant and on the ground underneath. Poor air circulation and dense growth make the problem worse, which I suspect is a major aspect in what is causing this to happen to your photinia.
Treatment starts with hygiene. Remove and dispose of affected leaves and fallen debris, and dispose of them, do not compost them. Prune your photinia to open the plant up so air can move through it, and if you are watering, ensure that you are doing so at the base rather than over the foliage.
If the problem keeps returning, apply a fungicide labelled for leaf spot on ornamentals such as Yates Liquid Copper Fungicide.
Keeping the plant healthy with good nutrition will also help reduce future outbreaks. So, an application of a slow-release fertiliser such as Scotts Osmocote All Purpose Controlled Release Fertiliser, to ensure it has the correct nutrients to fight back, would go a long way.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
