Tree Troubles – Nonspecific Symptoms

Fir and spruce trees are known for providing beauty and function in Nebraska.  Unfortunately, they’re also known for being hard to diagnose when troubles arise.

 

With most trees and shrubs, specific symptoms are present when they are ailing from insects, diseases and abiotic maladies.  That’s most trees and shrubs.  Not so much with fir and spruce.  In fact, over the years, I’ve sought out help from plant pathologists with diagnosis.  Most of these requests have led to a shrugging of the shoulders and a couple of times running the other way!

 

The problem is this – whenever a spruce or fir is struggling, the symptoms they produce are the same, no matter the cause.  They don’t produce round spots or marginal burning; just this sort of off color, sometimes purplish tint to the needles…sometimes falling off and sometimes not.  That’s it.  So, if the actual cause if overwatering or underwatering, root girdling or deep planting or a canker or root rot, the symptoms are the same.

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Classic diplodia tip blight symptoms

Without helpful signs and appearances, we’re left to investigate in other ways.  Gathering as much info as possible about the history of the site and noticing cues such as where the branches arise and how much growth has been produced in recent years is helpful.  Looking closely at the trunk and pulling back the mulch or fallen needles is also a good step, as clues or better symptoms may be found there.

planted too deep cory allan

Fir struggling from deep planting.  Photo credit (and feature photo): Cory Allan

John Fech
Horticulture Extension Educator at Nebraska Extension
John Fech is a horticulturist with the University of Nebraska-Lincoln and certified arborist with the International Society of Arboriculture. The author of 2 books and over 200 popular and trade journal articles, he focuses his time on teaching effective landscape maintenance techniques, water conservation, diagnosing turf and ornamental problems and encouraging effective bilingual communication in the green industry. He works extensively with the media to extend the message of landscape sustainability, making over 100 television and radio appearances each year.
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