As Arborists, you won’t often find us discouraging planting a certain type of tree. Some exceptions to this include: invasive species, fast-growing trees that make for difficult upkeep, or certain spruce trees. Specifically, blue spruce varieties which are susceptible to the fungal pathogen Rhizosphaera kalkhoffii, commonly known as needle cast.
If you have a susceptible spruce that is growing in your yard, you may find this advice has arrived too late! Unfortunately, blue spruce trees in the Madison area are nearly always carriers of the fungus. If your tree appears healthy, it is possible that the infection is in early stages and signs are not yet showing.
However, in most cases, you will notice the needles on your blue spruce begin looking sad. The fungal spores are carried by the wind until they locate a host. In this case, that is the beautiful spruce in your landscape.
Beginning on the lower branches and progressing from the inside out and bottom to top, your tree will slowly begin to shed needles. The lost needles will not grow back. In the case of severe infection, entire branches may die off in one season.
We are here to help! Early identification of the disease is the first step to a healthier tree. Once diagnosed by a Madison-area Arborist, a foliar treatment of a gentle copper fungicide is applied to the tree 2-3 times in the spring.
This treatment has shown a 70+% efficacy rate. While we’d like that number to be 100%, the fungicide we use is the best on the market. You will be providing your spruce tree with the best chance possible of survival.