Trident Maple Repotting:

What?
Root pruning is the cutting back of roots or the removal of roots from the tree. Repotting can use the same pot, or one smaller or larger, depending on the desired composition. It usually includes the addition of new soil to the potted tree.

When?
When the tree can be removed from winter protection, but before or just as the buds swell. Young trees (under twenty years) can be root pruned each year or every two years, older trees every two to four years. Trees can also be repotted after total leaf pruning. They should be protected and shaded for a week to ten days after root pruning and then gradually moved to full sun. This latter practice should be reserved for only very strong trees.

How?
Comb the roots out after removal from the pot. Then, with shears and/or knob or root cutters, remove roots that are next to the wall of the pot far enough into the root mass to enable you to add new soil all around the tree. Also, remove roots from the bottom of the tree and add new soil there. Cut into the root mass in a wedge shape and remove soil and sometimes roots from one or more areas around the tree so that over a period of years, all soil has been replaced. Large roots, when cut, should be cut on a slant facing up and outward. Roots should be be growing from all sides of the trunk without crowding, but radiating out from the trunk in all directions with open wedges in between.

Why?
To develop greater nebari--exposed roots that add to the beauty of the tree. Root pruning is important for the health of the tree. Old large roots only support the tree in the soil. Young root tips and microscopic root hairs are the absorbent areas of roots. Roots grow toward the edge of the pot and become free of soil. When roots are against the side of the pot they get hot and dry out much faster in summer. As these are the crucial absorptive roots, they need to be replaced by new roots growing into new soil.

Bud Pinching] [Branch Pruning] [Leaf Pruning] [Repotting]