University of Illinois Extension offices are already getting calls about needle evergreens that are not looking healthy, and spring has yet to arrive! If you drive your neighborhood right now, you can spot those evergreens that died late last fall. Arborvitaes are standing dead in many locations in the Fox Valley, as are Austrian pine and spruce.
Spruce are not well adapted to our area, and although they do grow pretty well for us when young, spruce begin to suffer as they mature. For example, Colorado blue spruce have been planted for many years and often as the focal point in a landscape. While young, few problems are apparent, but as they age, it is typical for them to have some trouble with needle blights and Cytospora canker.
Besides the dead Arborvitae that we can see, there are pines that died last fall too. Two common pines are Austrian (Black) Pine and White Pine. Austrian pine are loved because they create those beautiful candles as the new growth expands each year, and the white pines are chosen for their soft texture and the sound made as the wind blows through them. Austrian pines have performed well in landscapes being adaptable, yet like spruce, they are not at home here. Austrian pines have had several needle diseases, including Diplodia tip blight, and can have a combination of needle diseases at the same time. Just like the arborvitae, as temperatures rise, we can expect to see Austrian pine turn brown or just after they begin to grow, then turn. White pines, being more native to Illinois, fair better and tolerate needle diseases pretty well in a typical year, but they are not without problems. Take note that white pines still stressed from the 2012 drought are more prone to needle diseases.
What the University of Illinois Plant Clinic and I suspect plant clinics from our neighboring states are diagnosing are the more common needle diseases in increasing numbers on our spruce and pine. This increase in disease incidence will make it that much harder for our needle evergreens to recover and become healthy again.
Start this spring with the idea that our needle evergreens are stressed and that those needle diseases are present. Be sure those plants are well watered by nature or by you, and consider a fertilization to help energize the plants this spring. Make a note on your calendar to provide water starting in mid-August through mid- to late September, depending on the rainfall. Those high value evergreens in the home landscape can be treated by a professional arborist with fungicides yet as a homeowner we have to do our part as well if those plants are going to recover and grow for many more years.