Colorado Blue Spruce Decline
Our landscapes are changing. Many of you are seeing the problem Colorado Spruce is having in this part of the country. They are dying by the thousands wherever you go.
Allow me to digress...before we get into the spruce dilemma here is a point of clarification about dormant oil sprays that we talked about here a couple of weeks ago. We mentioned how affective this spray is in protecting our plants in the landscape because it is non-toxic and is one of the best eliminators of some of the most hard to control insects. An assumption was made that readers of this column would know what to spray with this material, apparently not all did. Due to the early spring now is the time to spray fruit trees, flowering shrubs- especially euonymus and evergreens like junipers, yews, pines and spruce(not blue spruce). All are subject to damage by mites, aphids, thrips and scale and this dormant oil spray is safe and provides excellent control. Be sure to read the label before using.
Back to the blue spruce decline problem...Spruce trees are dying because of an infection caused by weakened plants due to environmental stresses that have occurred over the past few years making these trees subject to secondary diseases. Things like drought and excessive heat can cause older plants to be weakened. Colorado spruce are native to Colorado at elevations of 6,000 to 10,000 feet with good drainage and cool temperatures. This particular spruce variety, unlike Norway spruce, must have additional care like deep watering, even for older trees, when there is a serious, extended drought. When this extra care doesn't happen, stress sets in the tree's system and complications result because of the weakened plant. This particular variety is not "at home" here and it is set-up for problems. For additional information go to http://michiganradio.org/post/why-are-spruce-trees-midwest-declining.
Roberts says "the Colorado blue spruce is the species of tree most affected. It seems to be a magnet for all sorts of diseases and pests," he says. One disease hitting spruce trees particularly hard right now is Phomopsis canker. And that disease has subsequently moved out into our landscapes and is virtually causing such a decline in many Colorado blue spruces that the trees are dying. — "Tree Doctor", Dave Roberts, Plant Pathologist, Michigan State University.
What is the solution to this dilemma? Unfortunately, there is no good answer for those trees that are affected with this decline, they will have to be removed. What type of evergreens should be used for replacements? Here are some suggestions: Norway spruce, arborvitae and pines are some of the choices.
Send any questions or comments to info@meadowview.com and we'll get back to you promptly.
Meadow View Growers
Growing since 1984