Certified GKH Gardening Expert
If it's newly planted, then the problem could be transplant shock. This article will help you with that: https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm It could also be an issue with underwatering. Check the soil to see if it's too dry. Water should correct this. Also, if you've fertilized it recently, it could have been too much, though the leaves would likely drop as well. Finally, it could be a fungus. Treating the plant with a fungicide should help with this.