Got Nature? Blog

Purdue Landscape Report: Many trees are planted for their beautiful fall color, especially in locations where the climate provides reliable autumn weather. I have said this multiple times during extension talks and conversations with submitters to the Purdue Pest & Plant Diagnostic Lab (PPDL), but I seem to have not experienced a ‘normal’ fall since moving to Indiana with how erratic the weather has been from year to year. Depending on weather conditions, such as high heat and drought, colors may develop early or may be duller for specific varieties than expected.

However, individual trees that begin to show fall colors earlier than expected (August, September, even early October) may be shouting out a proverbial cry for help. Plants will often show yellow or red foliage coloration during periods of stress, so this may occur at any point during spring, summer, or fall. Individual trees may also show fall coloration earlier than others of their species in the same area.  Now is the time to keep an eye out for this kind of early fall color as it can give you a heads-up on issues you can expect next year.

When examining a tree with early fall color, I would recommend checking the following:

• Is there a root flare?
  Purdue Landscape Report: Deep Planting article
  • If not – tree could be planted too deep or the soil grade may have been changed
• Is there any obvious damage to the trunk, root flare, or surface roots?
  • If so, there could internal decay that is not obvious and could be contributing to stress
• Are there any girdling roots?
  Purdue Landscape Report: Stem Girdling Roots article
  • If present, they could be affecting the vascular system and strangling the tree
• Is the rootzone mulched?
  • If not, the tree could be under stress from earlier drought, or weed and grass competition.
  • If so, make sure it is not mounded against the trunk of the tree
• Does the soil appear compacted? Was there construction near the tree within the last 5 years?
  • Compaction leads to issues with water, nutrient, and even oxygen availability to the roots and could lead to general decline

It is important to know the host species, but with the sheer volume of plant material available for sale in the nursery trade, it is even more important to know the cultivar that you are planting so you know what you might expect coming into the fall.

To view this full article and other Purdue Landscape Report articles, please visit Purdue Landscape Report.

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Resources:
Why Fall Color is Sometimes a Dud, Purdue Landscape Report
Forest Migration Plays a Role in Fall Foliage Colors, Purdue College of Agriculture News
U.S. Forest Service Fall Colors, Forest Service, U.S. Department of Agriculture
ID That Tree Fall Color: Sugar Maple, Purdue Extension – Forestry and Natural Resources YouTube Channel, ID That Tree Playlist
ID That Tree Fall Color Edition: Black Gum, Purdue Extension – FNR YouTube Channel, ID That Tree Playlist
Autumn Highlights Tour – South Campus, Purdue Arboretum Explorer
Why Leaves Change Color – the Physiological Basis, The Education Store, Purdue Extension resource center
Subscribe, Purdue Extension-Forestry and Natural Resources YouTube Channel
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension YouTube Channel
Summer Tree Care, Purdue Landscape Report
Tree Defect Identification, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – Forestry and Natural Resources
Surface Root Syndrome, The Education Store
Shrubs and Woody Vines of Indiana and the Midwest, The Education Store
Ask an Expert: Tree Selection and Planting, Purdue Extension-Forestry & Natural Resources (FNR) YouTube playlist
ID That Tree, Purdue Extension-FNR YouTube playlist

John Bonkowski, Plant Disease Diagnostician
Departments of Botany & Plant Pathology