University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Early Fall Color on Trees & Shrubs

August 13, 1998

With August nearly half gone, thoughts are already turning to school resuming and fall right around the corner. When shade trees start turning fall color early, are they just anticipating things ahead or having some kind of problem? Unfortunately, trees turning in late August most likely are stressed or in decline. Take some time to check these problem trees out.

While the color shows up in the canopy, start your inspection by looking down to the base of the tree. Root zones are key areas. Root damage is a very common stress factor that can lead to early fall color and decline. Types of damage may include direct injury from digging near the tree, injury from soil fill placed over the root zone, chemicals in the soil, excess water, or too little water. In addition, consider a girdling root to be a possibility, as roots growing across others or cutting into the trunk can be a serious problem.

Pay attention to the very base of the trunk. There should be a natural root flare in this location. If the trunk goes straight into the ground like a telephone pole, problems are likely to occur. This situation may be due to soil fill, girdling roots, or perhaps planting the tree too deeply.

Many of these root problems offer little in terms of solutions. Girdling roots can be cut after carefully digging away the soil. Most of the other problems are preventable but little can be done once damage has occurred.

Examine trunks for wounds of various types, perhaps from equipment, storms, winter damage, or animals. Since the "lifeline" of trees (sending up water and nutrients) is just under the bark, damage to trunks can have significant impact and may be why a tree is stressed and declining. Applying pruning wound dressing to damaged trunk areas is not suggested.

Certainly the weather also can play a part in adding stress to trees. Drought and severe winters can lead to tree decline; although neither is a leading cause here in 1998, past seasons could still be an influence on tree health.

The best overall suggestion for stressed trees is to avoid further stress. Water during drought periods, including fall. Perhaps fertilizing this fall or next spring may help. Also prune out dead wood, but avoid heavy pruning in late summer and early fall.


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