Research conducted over the past two decades has caused the University of Arizona, the International Society of Arboriculture, the American Forestry Association, and other arborist groups to revise guidelines for transplanting trees. The current transplanting guidelines are as follows:

Test soil drainage by filling the planting hole with water several times during the day. Wait 24 hours after the last filling. If water is still standing in the hole, drainage is poor. Poor drainage may be due to compaction, a hardpan (layer of caliche, bed rock, or clay), or a deep, heavy clay soil. Shallow, thin hardpans can be removed or pierced with drain holes. A drain hole should not be placed directly under the plant as this will force excess water to move through the root system and encourage suffocation or disease. Use good topsoil with similar texture to fill drain hole or replace excavated hardpans.

Another possibility is to add soil to increase the rooting depth. Sufficient soil should be added to provide two feet total depth over the entire rooting zone (one and a half to four times the mature tree canopy). Use soil that is similar in texture and set trees several inches above grade to allow for settling.

Mark an area three to five times the diameter of the root ball.

Till the entire area to a depth no deeper than the root ball. Measure the height of the soil in the container, not the height of the container, to determine how deep to till.

Dig a hole in the center of the tilled area that is only slightly wider and no deeper than the root ball. The root ball should sit on undisturbed soil.

The recommendation to limit the depth of the hole is due to the importance of ensuring that after the tree has settled, the root collar remains slightly higher than the surrounding soil. When a tree is planted in a deep hole which has been refilled it will invariably settle below the root collar, even when the backfill has been tightly packed. In addition, since the feeder roots will grow laterally and most will remain within one to two feet of the soil surface, there is no reason to dig a deep hole. Because the feeder roots will grow out, rather than down, it is beneficial to loosen the surrounding soil and make their progress easier. This is the reason for providing such a wide hole.

Always handle the plant by the container or the root ball. Remove the plant from the container with minimal disturbance to the root ball. With smaller containers this is usually possible by turning the plant upside down (use your hands to support the media) and striking the top edge of the container on a hard surface. In most cases the container will separate from the media.

Score the root ball to cut any circling roots. Make a vertical cut about 1/4" deep four times around the circumference and twice across the bottom.

Place the root ball in the hole. The top of the root ball should be level with or slightly above the soil surface. Backfill with unamended soil. Do not pack the soil around the root ball. The most satisfactory way of firming the soil and removing air pockets is to have the hose running into the hole as the backfill is replaced. Before finishing the filling process, make certain the plant is straight and at the proper depth; then complete the filling process with backfill.

Recent research has documented that adding organic matter to the backfill is not beneficial and may be harmful to the plant. Adding organic matter to the backfill ensures that the area which was the planting hole (and is now full of amended backfill) is different from the surrounding soil. Research has shown that rather than venture out into the native soil, roots will circle around within the planting hole.

Instead of incorporating organic matter in the backfill, use it as a mulch on top of the soil around the tree. This, in addition to being much easier, is better for the plant. The mulch will help hold in moisture, will moderate the soil temperature, reduce weeds, and will break down over time to provide nutrients for the tree.

Do not prune unnecessarily. Remove only broken or infected branches, double leaders, etc.

If you fertilize, apply only a low level of nitrogen (less than one pound of nitrogen per thousand square feet).

Remove nursery stake. Stake trees only if necessary. Use two stakes per tree. Put the stakes outside the root ball at right angles to the direction of the heaviest wind.

In order to determine where to place the ties connecting the trunk to the stakes, loosely hold the base of the trunk with one hand allowing the canopy to bend to the side (place your hand high enough on the trunk that the canopy bends only moderately with no major stress). Slowly glide your hand up the trunk until you reach the point that the tree is standing upright. Using your other hand slightly bend the canopy to one side. If the canopy does not return to the upright position, move the hand which is holding the trunk further up and try again. Find the lowest point on the trunk at which the canopy can return to an upright position after being bent to the side. Place ties six inches above this point. Use one set of ties only. Attach the ties so that the line between the trunk and the stake is parallel to the ground.

Use strong wire for ties. Protect the trunk by putting the wire through garden hose. The garden hose should be just long enough to loop around the trunk. Twist wires to keep the garden hose from migrating. The trunk should not move inside the garden hose loop.

Fasten wires to stake and twist to tighten. Wire should have sufficient slack to allow the trunk and garden hose to move as a unit.

Cut off the stakes below the lowest limbs of the canopy. It is very important to prevent limbs from rubbing against stakes.

Inspect and loosen wires periodically as tree grows. Remove stakes as soon as possible. All support should be removed from the tree within one year after planting. By the end of the first year the tree should have become established, and it has been reported that growth is actually reduced if the supports are left in place for longer periods of time.

If using manual irrigation, form an irrigation well by creating a dam circling the tree at the outer edge of the root ball. This ensures that the root ball media gets wet. Irrigate the plant and the entire tilled area. Apply sufficient water to thoroughly wet the soil to the depth of the root ball. This will remove air pockets without compacting the soil. Do not pack the soil around the root ball.

Mulch the entire tilled area to a depth of three to four inches with organic material. Do not let mulch contact the trunk. If planting in a lawn, keep grass away from the plant for as long as possible.

Water immediately following planting. Container grown plants need particular attention as they adapt to their new location. The well-drained organic mix in which plants are grown in the nursery is prone to rapid loss of moisture. Even though moisture is available in the soil surrounding the organic mix, it does not readily move into the root ball. Irrigation should be applied directly to the root ball every two days until the root system penetrates the surrounding soil backfill (approximately three to four weeks). Care must be taken not to allow the transplant root ball to dry out because the organic mix is very difficult to re-wet once it becomes dry. In this case, water should be applied two or three times each day until the root ball has been re-wet.

Plants in your landscape will require periodic maintenance to produce the best effects. This includes fertilization, winterizing, mulching, watering, and pruning.