News Release
October  22, 2007

Landscaping Tips: Autumn an excellent time to plant trees and shrubs

By Tom Heald, extension educator, UW CES

Autumn is an excellent time to plant trees and shrubs.

Why? Because in most instances the trees are dormant and, by planting them now, they are literally going to bed in your soil only to wake up next spring under your environmental conditions and not those of a nursery.

Given the choice between spring planting and autumn plantings for survivability, I’ve had far greater success in autumn. Consider, too, that many nurseries are willing to cut prices in autumn to avoid having to overwinter trees and shrubs. The savvy gardener can get spectacular deals this time of year!

Typically, you can plant up to the time the soil freezes, even if that’s mid-November.

The only exception to autumn plantings is evergreens. They can be successfully planted in the fall but only if supplemental water is provided throughout the winter, especially when the soil is dry.

Evergreens need extra watering in winter because they still “breathe” and release water through their needles. In Wyoming’s environment, it is sometimes impractical to water the root system in the midst of winter. The end result is often what’s called winter desiccation, in which the needles turn a brownish or reddish color. They literally dry up because the root system doesn’t have enough stored water to support the top growth.

Evergreens should receive a good soaking once a month during dry periods in the winter, while deciduous trees and shrubs should be watered once or twice during the winter.

Most native plants don’t absorb water through their leaves. Don’t spray the leaves, but focus on watering the roots. This is where water uptake occurs.                               

It’s important to water newly planted trees and shrubs frequently because they are establishing root systems. Establishment is a time when the plants are becoming balanced in the ability of foliage and roots to support each other.

Commercially sold plants are typically grown in containers. A one-gallon container-grown plant will take about a year to establish roots. Shrubs in a 3- to 5-gallon container will need about two years to become established. 

Container-grown trees follow the establishment rule of thumb of one year for transplanting and an additional year for each inch of trunk diameter. A 2-inch-diameter tree, for example, will take about three years to get established.

Trees and shrubs can also be purchased as “balled and burlapped” (B&B). Usually, these are the larger trees and shrubs.

In the case of B&B trees, root establishment takes longer because the diameter of the tree is larger, the root system is not in proportion to the above-ground part of the tree and some of the root system is cut away when the tree is dug from the soil, typically with a large, mechanical spade.

Care is needed to develop the root system during the critical time of establishment. Even though many native trees and shrubs are excellent at withstanding periods of drought, they have been grown in potting soil and should be watered as one would any other plant.

If planting shrubs or trees next spring or summer, the plants should receive three good soakings a week during hot periods, while as little as one watering a week will suffice in more moderate conditions.

Roots don’t grow into dry ground, so water both the potting soil and surrounding ground.

Don’t leave the plant sitting in a hole full of water surrounded by slow-to-drain clay. Plants can and do drown! Poke a finger or screwdriver into the ground to check for moisture in both the potting soil and surrounding ground to determine if the plant needs water. 

A number of University of Wyoming Cooperative Extension Service (UW CES) bulletins on trees and shrubs can be found at http://ces.uwyo.edu/PUBS/Horticulture/Horticulture_Publications_Main.htm.

The bulletins are also available at UW CES offices around the state. Contact information is at http://ces.uwyo.edu/Counties.asp. Telephone numbers and addresses for UW CES offices are also in the “Government Listings” section of phone books under “County.”

Contact: Robert Waggener, Editor
Phone: (307) 766-3571
E-mail: robertw@uwyo.edu

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