As the soil is put back into the hole, it could have some organic matter added as well. You don't want to make the soil added to the hole so good that the roots stay there. You want the roots to get out as far from the root ball as possible - loosening up the soil will help accomplish that.
Another thing that should be done to get the roots growing out is to make sure they are pointed out when they are planted. If the roots are in a pot and they are wrapped around themselves or the inside of the container, they should be unraveled, even if it means pruning a few to get them all loosened up. Roots that are twisted into a circle will always remain wrapped in a circle and could eventually choke themselves to death.
Remove all of the plastic pots, burlap, twine, wire and baskets that are around the root ball. None of these things will benefit the plant and all of them can inhibit the roots from growing.
If necessary, straighten the tree. Use water in the hole to help the tree roots slide around. Don't pull it straight and then stake it into place. When the stakes come out, it will still be leaning. Only stake it if the tree won't stay in place without help. Never stake it so rigidly that it can't move. The trunk needs to flex in the wind to build up its own strength.
Cover the root ball and the loosened soil areas with bark mulch to conserve water. Three to 4 inches is plenty. Don't pile any mulch on the tree trunk, now or in the future. If mulch is on the trunk of any of your trees, pull it back onto the roots and off the trunk.
Water the tree as necessary to keep the soil as moist as a damp sponge. Watering too often is as bad as not often enough; both will prevent good root growth. Water the tree as necessary for the next few years to keep the roots growing out into a wider area so that it will have a big enough root system to survive future droughts.
It is better to have a $10 plant in a $100 hole than a $100 plant in a $10 hole.
Q: Last fall, I thought I could save some money this spring by over-wintering some of my outdoor potted plants that looked so pretty. I thought they were doing well until this week. All of a sudden, the leaves are starting to fall off. I looked carefully and don't see any signs of insects. They are in a sunny window, and I have kept them watered carefully, too. Some of the leaves are falling off in full color and a few are slightly yellow. Others are drying up on the stems before they fall off. What can I do to save them so close to spring when I can put them back outside? It is still too cold to do that, I think, even during the daytime.
A: Unfortunately, this is a very common problem for people trying to keep their plants alive all winter. They survive almost through the whole winter, and then they die just before they can go back outside.
Many of the plants that are grown in pots during the summer are annuals and are not designed to stay alive indefinitely, even if they get good care. Annuals grow leaves for a while, then flowers, and then they are supposed to produce seeds and die. If you keep cutting off the old flowers, they can't produce seeds and they will stay alive longer, but they still usually won't last much more than a year.
Some of the summer plants are perennials that can live many years, if given the proper conditions. The problem is that indoor sunlight over the winter is usually just too dim for many of the plants to keep all their leaves. A bright greenhouse or sunroom that has windows on more than one side of the room will be better. A plant growing next to a window will need to be rotated so the whole plant gets light. If one side doesn't get light, the leaves will fall off as you described.