I have a few trees in a 'nursery' area that I have grown from seedlings. Several have gotten pretty big and I want to transplant them. I did this with a couple of silver maples in May or June and they didnt do very well. They lost most of their leaves and the tops died off completely. Now they look pretty good except they dont have tops. I dont want that to happen again when I move this next set out. I have another silver maple that is probably 1/2-3/4" diameter and a honeylocust that is 3/4-1". Are they too big for transplanting? Is now a good time to do it? What can I do to make sure to get enough of the root ball for them to survive? Thanks.

Transplanting any tree or shrub causes stress. However, both silver maple and honeylocust exhibit high tolerance to transplanting “shock”. The diameter distribution you indicated should not be a deterrent for success.

I would wait until fall (immediately after leaf drop) – this will allow needed time for additional fine-root development prior to the ground freezing. I personally prefer early spring transplanting – after the ground thaws and before the trees break dormancy. Regarding enough root ball – get an adequate tree spade to accommodate as much root system as possible based on your tree’s diameter. At minimum, I would plan for a root ball of 18-24 inches wide and 12 inches deep - the deeper and wider you go, the better off your tree will be. Remember to sever all roots prior to lifting. Experts also recommend soaking the soil with water two to three days prior to lifting.