For years, blue-green, perfectly triangular Colorado blue spruce trees seemed to dot the corners of half the lawns in Midwestern subdivisions.
Now, many of the older ones are losing needles and appearing to die from the top or from the bottom up.
Repeat the name slowly: Colo-rad-o blue spruce.
“They’re not native,” said Randy Setchell, owner of Ekana Nursery, Mendota. He said for years they were in great demand, and they’ve fared well for many years. And today, there’s still some demand for blue spruce species, to accentuate landscapes.
But as they age, cold, wet spring seasons with waterlogged soil, followed by hot Illinois summers tend to compound problems for them. In northern Illinois recently, they have become more susceptible to fungal diseases and insect attacks the older they get.
“There are multiple problems they are having. The first issue is almost every blue spruce in Illinois is stressed out,” said Julie Janoski, Plant Clinic Manager of Morton Arboretum.
Illinoisans are planting them in our clay, or other soil types that holds moisture longer than their native lands, where they live in rocky soil on mountainsides.
Other types of pines throughout Illinois also are under stress and attack from different types of diseases and insects, for some of the same climate and soil reasons, said Janoski,
However, after the ash trees dying from emerald ash borer infestations, Colorado blue spruce are at the top of the list of trees that are having problems in the region.
Trees worth saving
The staff at a Princeton-based tree service spends a considerable amount of time trying to save Colorado blue spruce from disease. Josh Taylor, certified arborist and vice president of Taylor’s Trees and Turf, said sometimes they get calls about problems with dozens of them on the perimeter of farmsteads.
“We get tons and tons of calls and we treat in the thousands of them (Colorado blue spruce) because we treat the windbreaks,” Taylor said. “There’s a multitude of things that can potentially go on and are active in our area right now.”
He could think of a couple of things that could cause die-back at the top of spruce trees.
The pine tip weevil, an insect that is native to Illinois, starts its invasion at the tender top of the tree. He said the trees often survive that, but they can cause the loss of the first few feet of the top of the tree. Another insect, Taylor said, is the ips beetle, a tiny beetle that leaves an exit hole and starts at the bottom. It also affects circulation to the top of the tree, so a property owner could see die-back on top and far-out branches.
Taylor said a lot of times, the needle cast fungus will pop up and then the ips or pine tip beetle move in, and all of those factors coupled with extreme weather and climate can kill a stressed tree.
“It’s one reason we promote using native trees,” Taylor said.
First comes stress, then more trouble
Janoski said as blue spruce age in northern Illinois, they become more susceptible to disease.
“There are a couple of fungal diseases causing a lot of damage,” Janoski said.
One disease is cytospora canker, which also can affect Norway spruce.
“It rarely affects trees that are less than 20 years old,” Janoski said. “Typically the bottom branches of the tree starts to die. On trees really severely infected you’ll see white resin or sap covering parts of the bark of the trunk. It’s slowly taking the tree out by killing the areas underneath the bark.
“Unfortunately for that one there’s no effective chemical control.”
Another fungal disease affecting blue spruce is rhizosphaera needle cast. It has some similar symptoms to cytospora canker, but it also can kill a stray branch farther up the tree. Owners will see the needles closest to the trunk drop off, and needles hanging on mainly to the ends of the branches.
“If you catch this one early enough … there is a pesticide that’s reasonably effective,” Janoski said of needle cast. But the treatments need take place for two years.
“If you suspect fungal disease cut those branches out and get them away from your property,” Janoski said, advising to stay safe and avoid cutting branches high in the tree.
Also, Janoski suggests cleaning up the needles that fall from trees with fungal disease, and then add mulch around them. She said the needle cast also can affect cones, so remove those, too.
Spruce trimming should occur during dry weather periods. Between cuts, clean cutting tools with 10 percent bleach or even household disinfectant to kill the fungus.
She said tree owners should make efforts to avoid injuring trees’ root systems; for example, don’t run heavy equipment over them.
Other precautions include watering trees during drought, mulching beneath them and making sure there’s good air circulation around the trees (don’t plant them in a clump).
Trees also can go into decline if they’re not planted properly or are planted to deep, said Diane Plewa, University of Illinois Extension specialist.
Sometimes if roots were cut before planting or burlap or a cardboard “cup” was left around the root ball, 10-15 years later, root girdling can occur and the tree can literally to choke itself, Plewa said.
Morton Arboretum recommends that all property managers and owners “plant some diversity so you protect your investment” — even for a 400-foot windbreak.
Colorado blue spruce still are popular for landscape accent, because of their blue-green needles, but the University of Illinois suggests alternatives such as Norway spruce, white spruce or Serbian spruce.
Janoski said Norway spruce are resistant to rhizosphaera needle cast, but not to all fungal diseases. Lately, the arboretum plant clinic has suggested that people who want a conical-shaped tree to try a Bosnian pine. She also has suggested hemlock, if the site is somewhat sheltered from wind, or arbor vitae (called white cedar by Wisconsinites).