This spring, I planted 5 American Hazelnut seedlings from my local conservation district. All are doing well, but one of them has developed patches of brown discoloration in the middle of it's new leaves. Interestingly, the plant looks healthy in every other way and shows no visible insect damage or signs of environmental stress, although it hasn't grown quite as fast or as big as the other 4 seedlings even though it gets a little more direct sun. At first, I thought it might indicate lack of water, but there is no change in texture within the browned leaf patches as I would expect with watering issues. Since none of the other seedlings have this leaf discoloration, I'm wondering what it is and what might be causing it. Is it a fungus? Or leaf scorch? Or could it just be natural variation in leaf color? Thanks so much for your help.