Getting to the root of the issue with tree planting

Fall is a great time to plant trees and shrubs. As the top of the plant moves into dormancy the soil is still warm enough for continued root growth.

Spring planting is often done bare root. This is nice as you can see the roots to correct any defects and make sure they spread out properly. Root problems that can’t be fixed with manipulation can be pruned out. Potted plants are a different story … or are they?

Fall-purchased woody plants have been in a pot for several months. The have been growing throughout the season. When you take the pot off you will usually see that the growing roots have been circling around the pot and have become “root bound”. To make matters worse the tree may have been repotted several times, so there may be several layers of bound roots within the root ball. There are often hidden problems in the root ball. In addition, these plants are often planted too deeply in the pot.

These root problems do not automatically heal themselves. Some of these roots may girdle the trunk or crossing and twisting roots may choke each other. Circling roots do not grow out into the native soil very readily. The soil may be too far up the trunk. These are all problems that may not affect a young tree, but as it grows it results in the death of the tree within five or ten years.

Recent and ongoing research provides a possible answer to these issues. In addition to proper hole preparation and removing pots, or baskets and burlap from the root ball, wash the soil off the roots before planting it again. There are several reasons this will help improve the success of tree planting.

• It is easier to see the proper planting depth. Place the root flare at, or slightly above, the soil level.
• Pliable roots can be spread out and stiff roots can be pruned off to greatly reduce the occurrence of crossing and girdling roots in older trees.
• Root defects can be found and corrected.
• Quicker establishment of roots into the native soil.
• Longer lived trees.

The procedure for root washing starts with preparing the planting hole before removing the pot, or wire basket and burlap of B&B (balled and burlapped) plants. You may need to soak the root ball before washing the roots. Be sure to handle the plants by the ball until the soil is washed off.

• Remove the soil with a stiff spray of water.
• Prune off broken roots.
• Prune stiff roots that cannot be corrected with gentle manipulation.
• Keep roots moist until the plant is in the ground.
• Place the plant in the hole so the root flare is at or slightly above the soil line.
• Arrange roots so they radiate out from the stem.
• Backfill the hole with native soil. Do not add amendments.
• Use water to soak the soil down around the roots. Do not step on the newly planted roots.
• Stake the tree loosely from three sides for the first year after planting.
• Water the plant properly every week during the growing season of the first year.