It may seem counterintuitive but the benefit of planting trees in the fall is one of horticulture’s best-kept secrets. There are many reasons to consider fall planting of trees and shrubs, some of which are very important in areas where hot, dry summers create especially difficult conditions for both newly planted and established trees.
Encourage underground development
Newly planted trees have small or weak root systems and are stressed even under the best conditions. Even carefully planted trees suffer damage to the root tips, diminishing water uptake. Planting in the fall enables root development when it is not necessary to also support a canopy of leaves. After leaves of deciduous trees have fallen, energy can go into root development, creating a stronger foundation for next year’s growth.
Reduce heat and drought stress
In summer heat, trees lose significant water through their leaves. Spring-planted trees with compromised root systems are often unable to take up water to transport to the tree canopy where it is desperately needed. This is one reason spring-planted trees often have a scorched appearance or drop leaves soon after planting, even when regularly watered. Newly planted trees should be nurtured with deep and regular watering for the first two years in areas with hot, dry summers.
Take advantage of fall moisture
Even the best of watering habits cannot mimic the natural delivery of water via precipitation. Because fall is typically a wetter season than summer, the natural moisture helps those roots become more established. A stronger, more developed root system is better able to find water in summer months when it’s more scarce. Fall tree planting is compatible with the natural cycles of weather and temperature while spring planting is more akin to attempting to bypass or conquer natural systems.
Most trees qualify
Most trees and woody shrubs benefit from fall planting. Generally, those with fibrous, numerous roots are best suited. Slow-growing trees, like oaks, may be less suited to this practice. Some popular trees that are not as well suited to fall planting include birch, fir, larch and hemlock. Shrubs that prefer spring planting include rhododendrons and azaleas — even though they have the fibrous root systems that would otherwise suggest fall planting is best.
Good advice is readily available
Confused yet? If you’re unsure which tree or shrub is best suited for your yard or whether fall is a good time to plant it, your local independent garden center is a great place to seek advice. In the frenzy of spring planting, garden center workers are operating at full speed, on full adrenaline and with little sleep. The most attentive may not be able to deliver the level of service desired. By fall, garden center staff members are rested, less frenzied and able to spend time with tree-planting clients seeking to invest in woody material.
Another resource is the Master Gardener plant clinic, open through September on Mondays, Wednesdays, and Fridays. In Klamath Falls, local tree professionals have partnered with the farmers market and Master Gardeners to provide a venue for learning and discussion around fall tree planting.
A final tip on tree care: In areas with dry summers, even mature trees need regular watering. While in wetter areas, two years of regular watering is considered sufficient before trees can access water themselves through their root systems, the lack of precipitation in dry regions during the growing season when trees need it most is stressful to the trees and contributes to slow growth and a variety of problems.
Irrigating your lawn is not the same as watering your trees. The thatch and thick mat of fibrous roots associated with turf soak up most irrigation water before tree roots can access it. Mature trees benefit from a deep, regular soaking of the roots at the drip line at the edge of the tree’s canopy — not at the base of the trunk, where structural roots dominate.