Spring Freeze “Wounds” On Trees Not Going Away - by Jim Low

Story by: Guest Contributor

First posted on 09-21-2007

Following the recovery of trees and other landscape plants damaged by this year’s record-breaking spring freeze, some homeowners are surprised to find lasting problems in plants that have appeared to grow normally for several months.

“With the recovery that has occurred from the spring freeze, it is sometimes hard to remember that there may be lasting problems showing up later,” said Simeon Wright, coordinator of the University of Missouri Plant Diagnostic Clinic.

Over the past few months, Wright’s clinic has received numerous samples of plants damaged by the spring freeze followed by summer drought.

“In some cases, wounds that were created when the plant tissue froze after coming out of dormancy have become infected, or stress from the summer drought has weakened vascular tissues, which leads to cankers,” he said.

Cankers are infections of a stem or trunk of a plant, which destroy the water-conducting tissues, and the branch wilts and dies, he said.

“We’ve received willow, blueberry, juniper, sycamore, maple and Austrian pine with cankers or areas of stem, branch and trunk damage that girdle the plant,” he said.

With many of these plants, the obvious symptoms were small to large portions of the plant suddenly wilting and dying.

It is important to remember to trace the dieback to where the healthy tissue is present and look for a canker. Clues include cracks, loose bark, a sunken area or oozing sap.

“This is the portion of the plant we need to look at for diagnosis,” he said.

Control measures will depend on specific diagnosis, but often the best thing to do is to prune out the cankers when possible and continue watering if dry weather continues, he said.

Wright examines more than 500 plant and insect samples sent to his lab each year.

Submit samples directly to the clinic or through any local MU Extension office. The general fee for plant analysis is $15. For more information go to http://soilplantlab.missouri.edu/plant or contact the soil testing and plant diagnostic services at 573-882-0603.

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