By Gail Ruhl, Senior Plant Disease Diagnostician, Interim P&PDL Director, Purdue University
Click on image to enlarge.
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Wabash River flooding
the Lafayette Municipal Golf Course |
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Are your trees treading water with the recent deluge of rain? The
natural question is how long can trees survive flooding before injury
results? According to Jeff Iles, Extension Horticulturalist, Iowa State
University, the prospect for survival and continued growth is good
if flood waters recede in seven days or less. However, if flood waters
cover roots of sensitive trees for longer periods, symptoms of injury
such as leaf chlorosis (yellowing), downward curling of leaves, leaf
drop, and branch dieback may occur.
Following the recession of flood waters, saturated, poorly-drained
soils will continue to pose a great hazard for trees, since oxygen
is unavailable to roots in waterlogged conditions. Another hidden danger
that may result from flooding is the deposition of sediment over tree
roots. Silt and sand deposited over feeder roots to a depth greater
than three inches may impede movement of oxygen to tree roots, especially
on small or newly-planted trees. If feasible, sediment should be removed.
Recovery practices include enhancing the vigor of flood-stressed trees
by following proper tree maintenance practices and eliminating additional
stress. Fertilization is not a cure or remedy for root injury caused
by flooding. Dead or severely cankered branches should be removed as
soon as possible; other corrective pruning should be done during the
dormant season.
Aerating the soil, mulching, and watering during extended dry periods
are recommended practices that may help enhance vigor, but they are
not rescue treatments for severely injured trees. For future landscaping
plans, avoid planting sensitive species in flood-prone areas.
For more information on flooding and trees, go to:
Understanding the Effects of Flooding on Trees (IA)
http://www.extension.iastate.edu/Publications/SUL1.pdf (PDF
124K)
After the Storm; Garden and Landscape Triage
http://www.hort.purdue.edu/ext/storm2003.html
Storm Damage to Trees and Landscape Plants
http://bluestem.hort.purdue.edu/plant/stormdamage.html
Click on "flood damage."
Flooding and Its Effects on Trees (USDA Forest Service)
http://www.na.fs.fed.us/spfo/pubs/n_resource/flood/cover.htm
Landscape Plants for Moist to Slightly Moist Areas HO-226
http://www.hort.purdue.edu/hort/ext/Pubs/HO/HO_226.pdf
Landscape Plants for Wet Areas HO-227
http://www.hort.purdue.edu/hort/ext/Pubs/HO/HO_227.pdf
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Information listed is valid only for the state of Indiana.