By Jeff Burbrink, Extension Educator, Purdue Extension Elkhart County

GOSHEN — About five years ago, the number of calls and plant samples concerning Colorado blue spruce began to increase dramatically in the Extension Office. The clients often described having several spruce trees in various states of decline and were desperately seeking a solution to the problem.

As you drive around the area, it is fairly easy to spot spruce trees going through decline, especially on the lower branches. It has even affected two trees on my own property.

The key symptom for spruce decline is branch dieback, usually on lower limbs. Over a 2-4 year period of time, the needles will thin, making the plant’s appearance unacceptable for most homeowners. The problem is related to an increase in several diseases that attack spruces.

Needlecast is one of those diseases. Needlecast fungi attack the current year’s needles, but the needles do not fall off until the following season. The result is a tree with an “outer shell” of live needles and dead needles inside. Two diseases cause this problem, rhizosphere and stigmina.

Another disease is tip blight. Tip blight affects the new growth, causing it to die back. Phomopsis and diplodia tip blight are the most common example of this in our area.

Another disease, known as cytospora canker, infects branches or the main trunk. The cankers are sunken or ridged areas that ooze resin, which often will turn a white color. As the cankers develop, they can interfere with the trees ability to move water and nutrients and eventually the branch can die.

Why is this happening? Part of this is related to climate. Colorado Spruce is native to arid regions in the Rocky Mountains. Our region is much more humid, which is ideal for these diseases. In landscapes, spruce are often on marginal sites as windbreaks or screens, and as a result, they are stressed and more susceptible to disease.

What can be done? In most cases, not a whole lot. For most diseases, fungicides may be effective in preventing the disease, but the products have to be in place before the symptoms appear.

For preventative control to be successful, the tree must be treated numerous times and probably over several years.  Most of us do not have the financial resources or time to do this job ourselves, especially on larger trees.

In most cases, the effectiveness of fungicides is going to be limited because the plants have the disease(s) before homeowner notices there is an issue. Removing affected branches is usually the best action to improve the trees appearance and slow the spread of the disease within the tree.

Overall, the future does not look promising for the beloved blue spruce in our region. Alternatives to blue spruce in the landscape include the concolor fir, dawn redwood, Serbian Spruce, Swiss stone pine, Korean Pine and Bald Cyprus. Each of these trees has a preferred set of conditions they thrive in, so as you explore your options, be sure to select trees that meet your soil type and conditions.

For more information about the decline of spruce in the Great Lakes area, I suggest reading an excellent publication at http://tinyurl.com/hrfx9vq from Michigan State Extension, as well as the additional resources linked at the end of the webpage.