The Purdue Plant and Pest Diagnostic Laboratory

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May 16, 2013

Drought of 2012: The Aftermath

Tom Creswell, Director and Gail Ruhl, Sr. Plant Disease Diagnostician, Plant & Pest Diagnostic Lab
Lindsey Purcell, Urban Forestry Specialist, Department of Forestry & Natural Resources

The drought of 2012 may be officially over but the damage it caused will linger on. Many trees and shrubs were badly stressed by the extended drought last summer and as new growth is emerging this spring we are beginning to see the full extent of the damage. Some trees that appeared to be unharmed going into winter are now failing to produce new growth and have died or lost major branches. The pictures here show an example of a large white oak that received no irrigation last year. The drought alone would not normally kill a well-established, healthy, white oak in a single season. The tipping point for this tree was the combination of drought, a root system restricted by pavement, soil compaction and competition for water and nutrients with the surrounding trees. As you notice trees failing to thrive this spring, think back to last summer and fall and remember we suffered one of the worst droughts in 100 years. Trees and shrubs that were not irrigated or were in marginal sites may just now be showing the effects of water deficits.

Proper care of drought-stressed trees during the coming summer will be critical. Lindsey Purcell, Purdue Urban Forestry Specialist recommends the following:

  • mulch trees with 2-3 inches of fresh organic mulch (keeping it away from the trunk)
  • prune out all dead wood
  • make sure plantings get 1 inch of water each week from either irrigation or rain
  • do not fertilize this year as this will only stress the tree/shrubs by forcing new growth

Click image to enlarge

Stressed oak

Stressed oak trunk

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service