Sonoma County Garden Doctors: How to plant a bare root tree

Tom G. of Santa Rosa asks: I would like to purchase a few bare root fruit trees and could use some guidance in planting them correctly.

All fruit trees should be planted where they will get sun for at least six hours or more a day, have well-draining soil, and receive adequate water. Fruit trees can be planted at any time of the year, but when purchased bare root during the winter, they should be planted soon after you purchase them.

If they cannot be planted quickly they can be temporarily "heeled in," where you cover the roots with compost, sawdust, shavings, soil, etc. Make sure to keep the roots moist until you can plant them.

If your soil is heavy and/or compacted, dig the planting area a couple of feet wider than the width of the root system, and not much deeper than the longest of the roots, as roots will not grow through densely compacted soil.

Toss a few shovelfuls of well-decomposed compost on top of the soil before digging the hole. Dig the planting hole at least twice as wide as the spread of the tree's roots, but no deeper than the depth of the root ball.

In many gardens, there might be the presence of an impervious layer of "hardpan" or "claypan" found within one to two feet of the surface. You need to break through this hard layer to allow for drainage and root growth. You might need to break through this hardpan with a pickax or jackhammer (available at equipment rental outlets).

If this is not possible and there's no way to get through it, then you will need to find another spot for the tree or build a raised bed one to two feet high and fill it with a good-quality soil.

Before you do anything, examine the roots of the bare-root trees and prune off any roots that are broken or kinked. Place the tree in the hole with the graft union above the soil surface. Orient the weaker side of the graft northeast to reduce the likelihood of sunburn.

Start filling the hole with the same soil that you dug out, making sure the soil gets underneath the roots to eliminate air pockets. When properly planted, the soil line on the trunk of the tree should be about 1 to 2 inches above the level of the existing soil line.

As a general rule, once the soil has settled, the largest roots should be just below the soil surface. The soil should slope away from the tree to prevent standing water near or on the trunk.

Water the tree thoroughly to settle the soil around the root ball. A layer of mulch 3 to 6 inches deep, such as compost and wood chips, will help control weeds and conserve moisture.

Keep the mulch a few inches away from the trunk to prevent crown rot and hiding places for insect pests.

Protect the bark of the tree from sunburn and borer insects. For this purpose, mix equal amounts of white water-based paint and water.

Paint the mixture from the soil surface up, all around the trunk to the first branches. They shouldn't need painting again.

It is important to prune young trees so they can begin to develop into a tree with the correct structure.