What’s wrong with my Blue Spruce? It used to be so healthy and lately it looks terrible. What’s wrong and what can I do?
Colorado Blue Spruce is native to the mountains of Colorado. Over the past half century, landscapers, homeowners, and Christmas tree growers started planting Blue Spruce. They were a great selection with a blue green color and grew very conical without much pruning.
So, what happened?
A variety of insects, fungus, disease, and environmental issues can affect Blue Spruce. Being native to the west, they are adapted to grow in dryer climates with wind and cool temperatures.
Ohio springs has become wetter over the past decade. So, the first problem your Blue Spruce is encountering may be Rhizosphera, which is a fungal disease that can attack the tree from the bottom up. Initially, just a couple of bottom branches will begin to die. The tree will continue to show signs of infection and over the coming years will lose more lower needles. Eventually the tree will lose most of its needles and should be cut down. A couple of options is to treat the tree in the springtime with fungicides. Also, limbing up the lower branches will help to increase air flow, which helps to slow the infection.
What about insects? Blue Spruce can be attacked by bagworm. Insecticides need to be applied when new larvae emerge and begin to feed and build their bags.
Spruce Spider Mites can attack needles in the spring but will not show signs of damage until summer/fall.
White Pine Weevil can attack the central leader on not only White Pine but also, Blue Spruce.
In the spring, the weevil will emerge from the soil and then crawl up the tree to the leader and insert eggs in the leader. Larvae emerge and will bore into the stem and kill the leader. But not all Blue Spruce are doomed. If the get good air circulation and appropriate moisture, they can survive relatively well.
I am often asked “What can be planted as a substitute for Blue Spruce?
Concolor or AKA White Fir has a blue green needle, conical shape but need to be planted in a well-drained site. They ‘HATE” wet feet. Another possible replacement is Norway Spruce although they will not have the blue green color.
If you want to try or save your Blue Spruce, below are links for care for the following problems:
White Pine Weevil Prevention:
https://www.canr.msu.edu/news/control_white_pine_weevil_in_early_spring#:~:text=Contact%20pyrethroid%20insecticides%20such%20as,for%20bark%20beetles%20or%20borers.
Rhizosphera Control: https://u.osu.edu/ornamentaldiseasefacts/nursery/rhizosphaera-needle-cast/what-is-it-what-to-do-about-it/
Bagworm Control: https://bygl.osu.edu/node/2152
Spruce Spider Mite Control: https://ohioline.osu.edu/factsheet/HYG-2012-11
Good luck “sprucing” up your landscape.