Q.Indian hawthorn
I have 4 along my fence. 3 thrive but the one slowly dies over a 1 1/2 -2 year time period. I have replaced it 3 times. The last time I dug out and replaced the soil. All are on a drip system and basically in full sun. Would like to try again to keep the uniformity in the yard.
These articles will help refresh you on the care requirements and have information that should help you pinpoint the issue.
https://www.gardeningknowhow.com/ornamental/shrubs/indian-hawthorn/growing-indian-hawthorn.htm
https://www.gardeningknowhow.com/ornamental/shrubs/indian-hawthorn/indian-hawthorn-pruning.htm
http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/hawthorn-diseases