Tree Davis: Fall tree planting 101

By Sydney Vergis

As fall colors start to emerge, tree planting season begins here in Davis. Cooler temperatures allow for new trees to establish their roots, without the stress of the heat.

Are you thinking about planting a tree in your front or back yard? The success of that tree will be dependent largely on if it is placed in the right location. You’ll want to take note of nearby buildings and power lines and then compare that with the average height, canopy spread, growth rate and soil, sun and water requirements of the trees you are considering planting.

The city of Davis uses a master tree list as a guide for selecting a city street tree, which could be a good place to start looking for information on trees that might “fit” in your landscaping plans. Once you have selected the tree you are interested in planting, you’ll want to follow these steps:

* Prepare and dig the planting area. Make sure to dig a planting area that is two to three times the diameter of your tree’s root ball, and no deeper than your tree’s root ball. The sides of the holes should be rough and uneven, which can help new roots grow out into surrounding soil. Before you dig, call 811 and make sure you know what’s below.

* If the tree is in a container, gently remove the container from the tree’s root ball — don’t pull by the trunk. Loosen the tree roots with your fingertips and prune away damaged or circling roots.

* Loosen the soil near the trunk to find the area where the trunk gets wider as the first roots join the trunk. This is called the “trunk flare.”

* Place the tree in the hole. The bottom of the ball should rest on solid, undisturbed soil. Make sure that when you have filled in the hole with soil, the trunk flare is at or just above the soil surface. Make sure you have not planted your tree too deep! This can cause bark to rot.

* Stand back and look at the tree before putting the soil back into the hole. You can make careful adjustments at this time to the planting height and the direction the branches face without seriously harming the roots.

* Gently backfill the original soil removed earlier. Do not add fertilizer, compost or other material. Use one-third of the soil at a time and break up dirt clods and remove any grass, weeds or rocks. Lightly pack the soil with the shovel handle to remove air pockets. Do not stamp on or compress soil heavily since the best soil for root growth has spaces for both air and water, but not large air pockets, which causes problems.

Water briefly. Refill and pack again until soil is even with top of root ball. The trunk flare should be slightly above the soil. Water thoroughly.

* Cover the entire loosened area of soil with 3 to 4 inches of mulch (chipped wood or bark, compost or dry leaves). Mulch will slow water loss, reduce competition from weeds and grasses, moderate soil temperature and provide a small amount of nutrients. But keep the mulch away from trunk of tree to prevent disease.

Stake the tree only if you think tree stability is a problem. Stalking should be used as a temporary measure to allow the tree trunk to develop strength and should be removed as soon as possible.

If you are interested in learning more, this material and more is available through the “Tree Guide for Davis” on our website, treedavis.org. This guide was created with the support of the Pacific Gas & Electric Co. and the California Center for Urban Horticulture Partnership.

Tree Davis is a nonprofit organization committed to inspiring people to plant and care for trees, and to promoting environmental awareness and stewardship. If you are interested in using the planting skills outlined here, volunteer information for local tree planning events is available at treedavis.org.

— Sydney Vergis is a Tree Davis volunteer. This column is published monthly.