Fall is an excellent time to assess and care for existing trees in your yard and plant new trees. Too often homeowners don’t pay enough attention to the structure and health of their trees and only discover problems after a storm when trees or limbs fall to the ground (or on the house). Healthy trees with a strong structure are more resilient to storms. Proper maintenance while trees are young can help develop well-formed and structurally sound trees.
Planting trees and letting nature take its course is not the best approach for urban environments. Steve Green, a master arborist in Springfield, explains that trees achieve their best health and structure when they grow together in forests.
“Open grown trees, which is the norm in the urban landscape, do not have the advantage of neighboring trees shading out lower limbs, which most shade trees will eventually self-prune,” said Green. “Consequently, responsible tree owners should assume responsibility for helping them achieve good form and structure.”
Late fall or early winter after leaves have fallen is an ideal time for structural pruning because the architecture of the tree is visible. However, some species, especially oaks and elms, should only be pruned when they are dormant in order to avoid insect infestation. Live wood should not be pruned during the growing season.
Guy Sternberg is an internationally known oak expert who has operated Starhill Forest Arboretum in Petersburg for 50 years. He is the author of Pruning Oaks: Training the Young to Achieve Grandeur.
“Training young trees may be one of the most important, yet most neglected, procedures in growing oaks,” writes Sternberg. “These trees need to be pruned correctly when they are young in order to develop into the long-lived patriarchs that are their potential.”
He says careful, proper pruning (small, timely cuts) spread over time during the early years results in a superior tree.
Addressing structural development involves eliminating codominant leaders, parallel branches, whorls, water sprouts, inward-directed growth, girdling roots and damage. For biological health, it is as important to know what and when not to prune to avoid diminishing the tree’s vital resistance to pests.
This can be challenging for non-experts. Consulting a certified arborist can be extremely worthwhile. Find a certified arborist in your area at https://illinoisarborist.org/. Prevention can be the best medicine. Pruning is far cheaper than tree removal and can expand the tree’s life span. Anyone who has hired tree companies to remove large trees, clean up sizable branches and address damage knows how expensive that can be. Certified arborists trained in tree health can identify issues that need addressing and evaluate potential risks.
Pay attention to changes in trees over time. By taking pictures seasonally, it’s possible to track changes which may be a warning sign. Alterations to sidewalks, driveways or landscaping can impact trees, and results may not be seen immediately. Most homeowners don’t look high up into the canopy and lack a trained eye to see potential problems.
Healthy roots help whole trees thrive. Green says fall is a good time to consider organic matter supplement, biochar addition, vertical mulching and other things that benefit the area where tree roots proliferate. Apply mulch around trees leaving a two-inch gap between the mulch and the trunk. Avoid piling mulch higher onto the trunk.
Watering is also critical. The Morton Arboretum website provides extensive guidance. Highlights include watering trees and shrubs based on soil and weather conditions, not on a specific schedule. To check the soil’s moisture, insert a hand trowel into the soil and tip out an inch or two of soil. If the soil is dry, it’s time to water. Deep watering is important to allow water to penetrate the soil at least five or six inches. Watering thoroughly and less frequently is better than frequent, light watering.
Watering trees around the drip line (under the ends of the branches) is the location of the roots most able to take up water effectively. Trees and shrubs, especially those newly planted, need ample water in their root systems as they prepare for winter. There is no specific cutoff date to stop watering in the fall. Watering should continue as long as the soil is not frozen, depending on weather and soil conditions.
Fall is also an excellent time to plant deciduous trees. Sternberg says trees, such as oaks, that don’t root well in the fall are best planted in spring. Trees planted in the fall need at least six weeks before freezing in order to become established. Sternberg says trees should be planted at the exact recommended depth with a properly prepared soil opening that is very wide and no deeper than the trees’ roots. When taking trees out of pots, straighten or prune circling roots; otherwise, the tree may girdle itself.
Buy from reputable companies, and look for any indication of damage or disease before purchasing. Avoid planting what everyone else is planting in your neighborhood. Tree diversity is critical to avoid problems in the future if one species comes under attack. Emerald ash borer destruction of vast numbers of ash trees throughout communities is an example of a problem when too many trees of one species dominate the landscape. Consider planting native species, contemplate how the tree will grow over time and avoid planting too close to structures and sidewalks. Make sure there is enough space and appropriate soil for the root system to develop.
Trees provide numerous environmental and economic benefits and enhance communities. Take time in the fall to do your part to care for trees in our urban environment.
Karen Ackerman Witter has a background in natural resources and has consulted both Guy Sternberg and Steve Green about large and small trees in her yard.
There are numerous online resources to help guide homeowners. The Urban Tree Foundation is one https://urbantree.org/prunehome.shtml. The Morton Arboretum provides a wealth of information about selecting and planting trees, watering and mulching, pruning trees and more https://mortonarb.org/plant-and-protect/chicago-region-trees-initiative/how-to-care-for-trees/.
This article appears in September 24-30, 2026.
