Our neon flash spirea got this burnt at the edge of its leaves. And the burnt area are getting crisp. Do you know what might have caused this symptom? Is it some sort of disease or it's just simply dying? Any chance of over/under water? or the exposure to the sun? We kept it our semi-shade area during the past 2 weeks though. Now I moved it to the area with more sun exposure (although not sure whether it is the way to go.)

We bought it from a home improvement center only 2 weeks ago and haven't got round to put it in the ground just yet. Appreciate your suggestion/remedy.