This spring, I have had several calls about evergreen trees. People have noticed that their spruce trees are turning brown, usually at the ends of the branches. The question is whether or not this is a disease. In many cases, it is not and is because of the extreme cold temperatures this past winter. The key elements here are timing of damage and location of damage. In terms of timing, the trees were fine last fall and then damage showed up this winter. The location of the damage is at the end of the branches and in a lot of cases, all over the tree.
There are a couple of spruce needle diseases (Rhizosphaera needlecast and Stigmina needlecast) in Kansas that will cause a needle scorch and needle drop. These fungal diseases attack spruce needles in the bottom and the interior portion of the tree. Also, the infection period is during the spring or early summer when the weather is wet. So, for the spruce trees with similar damage, the problem is actually the result of some desiccating winter winds.
During the winter, evergreen foliage still transpires, which is giving off water vapor. On windy days the rate of transpiration is high and if the ground is frozen or dry then the roots may not be able to keep up with the demand. Low temperatures play a role as well. The result is scorched spruce needles. The damage tends to be greatest on the outer foliage which is most exposed. So what does this mean for the recovery of the tree? Unfortunately, spruce trees do not handle winter damage well. Anything that damages spruce needles and turns them brown will result in defoliation and in most cases a branch die back. The best time to assess the extent of the damage and the potential for recovery is mid-May. By this time, new growth should have developed and it will be clear if the buds are going to put on some new growth. You can also check for potential recovery by pulling off a few buds. If they are brown inside, don’t expect any new growth. If the buds are green inside, the spruce tree may put on some new growth. Winter damage or winter desiccation is common on pine trees as well spruce. When the needles on pine trees are damaged, they turn brown and eventually shed. However, they usually put on a new set of needles the following spring. Pine trees are pretty resilient to this kind of damage. Regular watering is always a plus when the tree is under stress. As always, if you are not sure if what you are seeing in terms of damage with your evergreens, you can email me a picture of the tree and I can help you figure out what is wrong, you can also call the office, and I will be happy to set up a time to look at your trees.
Alicia Boor is the Agriculture and Natural Resources agent for Barton County K-State Research and Extension. You can contact her by e-mail at aboor@ksu.edu or calling 620-793-1910