I have a mexican redbud which I've had for 2 years now. It grows very vigorously, but I notice that a lot of the very new, small leaves burn easily. It doesn't seem to bother the plant. I am in New Jersey, zone 5-6 and we have had tons of rain, so dryness isn't the problem. Also, the area where it is drains readily, so excess water isn't the culprit either. Is this normal for the redbud?