We love evergreens in the winter time, where their deep greens or silvery blues stand out against a drab or snowy background. Colorado blue spruce (Picea pungens) is in the blue category, and even in the dead of summer, offers a cooling scene in the landscape.
Colorado blue spruce needle cast USDA Forest Service – North Central Research Station , USDA Forest Service, Bugwood.org
But this beautiful conifer has inched its way onto the do-not-plant list over the last several years. Not because it’s invasive, but because it’s a disease magnet and struggles in the non-Colorado soil of the Indiana landscape. No spruce is native in Indiana.
“I haven’t used Colorado spruce in probably 10 years,” he said. “We still get requests, but quickly and firmly discourage their use. Most people understand and certainly don’t want to spend money on something that is prone to failure.”
Purdue lab reports drop in spruce samples
Purdue’s Plant and Pest Diagnostic Laboratory gets a few diseased Colorado spruce samples a year, but “most landscapes know to avoid it now. Most of the samples are from mature trees that are being maintained with fungicide sprays,” said Tom C. Creswell, clinical engagement professor at the lab.
“We get more samples of Norway spruce (Picea abies) now than blue spruce, mainly environmental stress and Phomopsis dieback,” he said. Spruces also get spider mites, which shows up in cool weather.
For that cool blue look, Gorden said the dwarf varieties ‘Globosa’, and ‘Montgomery’ are good substitutes. “They don’t seem to have the same issues.”