I planted these three from seed all at the same time 2 or 3 years ago. One of them is getting very tall, but is too spindly to stay upright on its own. What can I do to correct this? The other two are much smaller, which I find odd because all of them have been kept together in the same location. Is this unusual? When I planted them I used regular bagged (purchased) garden soil mixed with some of the dirt from my compost pile. The yellow marks on the leaves are from putting them outside last summer in a plastic greenhouse. The door flap was left open but I think the reflection of the sun on the plastic burned the leaves. I know very little about growing trees and tried this as an experiment, but now I don't know what I should do to properly care for them. Any tips or advice would be much appreciated.