What’s wrong with the spruces?

Norway spruce was the first tree I ever planted. It came from Sears, back in a time and place when Sears stores had nurseries.

My dad and I planted the small tree in our backyard, where it proceeded to loom over the house and driveway in the time it took me to get through high school. Fast-growing evergreens certainly have a place in our landscapes, and serve important duties there. Now that certain diseases have come around though, we find that spruces — especially Norway and blue — face problems not easily overcome.

So the culprits have been around for decades, but conditions favor their spread more and more, and the destruction that wreaks. Cytospora, Rhizosphaera and Stigmina are three different funguses with similar outcomes: they kill spruces. Slowly. You may have one of these spruces in your life at present, or maybe in your past.

Prevention and treatment

Native range for spruces is the northern latitudes, or mountainsides in temperate latitudes. The Colorado blue spruce, popular in the nursery trade for many years, is native to the Rocky Mountains. Try as we may to select genetics more suited to our summer heat, humidity and occasional drought, the blue spruce can become stressed and then susceptible to disease. Norway spruce runs into the same issues.

If you have a blue or Norway spruce that’s doing fine, great! Keep doing what you’re doing. Spruces that do well hereabouts may have one or more of these things going for them:

Good air circulation, which limits the fungus. Consider the wind direction and nearby buildings.

Spacing that provides for that air circulation, which means enough room to grow to maturity. Resist the temptation to plant for “instant effect.”

A “cool root run,” meaning that the root area is shaded and/or mulched suitably.

The soil has adequate organic matter, perhaps 3 to 5 percent. Most soils are low.

Adequate soil moisture, but not too much.

Trees showing signs of fungal infection — often going brown from the bottom up — may benefit from fungicide sprays. Do know that treatments are only preventative and can never bring needles back to bare branches or clear up infected tissue. I would say to do this in the spirit of experimentation, because success can’t be guaranteed, and treatment comes at some expense.

Early spring is usually the time to start, and treatment at intervals through the spring and into summer is the typical drill. Have a look at this publication from the University of Illinois for details on spruce problems and treatments: web.extension.illinois.edu/plantclinic/downloads/Plant%20Clinic%20Report%20Spruce.pdf.

Which spruces to plant?

If you are looking to plant spruce, consider a species that’s better adapted to our Midwestern summers. Black Hills spruce is a good one. Serbian does pretty well, too. Or maybe you would consider an evergreen that’s not a conifer. Some folks have great results with American or Foster holly, which also provide food for migrating songbirds.

Regardless, keep in mind that life isn’t so easy for the spruces anymore. Choose well and plant with care.