Blue spruce help

Asked August 24, 2019, 12:51 PM EDT

I have 6 blue spruce trees about 3 years old since planted on my property that don’t look healthy. Started about 7 feet tall. Now about 9’. They are in full sun in a fairly windy/breezy/open area and the solid type is hard and mostly clay. I just took a branch sample to a local nursery and under the microscope it showed a bunch of black spots, fungus I believe. I have TruGreen fertilizing and applying a pesticide and I think they did apply a general fungicide recently. Should I trim off the dead branches at the bottom and should I drive 1”-2” holes around the tree as recommended? Should I also invest in some mulch (cedar) around them? I also just did apply some Jonathan Green Love Your Soil for hard souls around the area. Any help will be much appreciated

Washtenaw County Michigan blue spruce declining pine tree trimming

1 Response

Hello,

Unfortunately, blue spruce is not recommended for Michigan as it is too humid here which makes the tree prone to needle blights and fungi. This is what you are seeing on your spruce. They also prefer well draining, moist, loamy soils, not clay.

Trimming the lower branches off will remove some of the fungi, but they are always present in the environment. During the wet spring you will need to apply fungicide every year. https://www.canr.msu.edu/news/what_is_spruce_decline_and_what_should_you_do_about_it

Be careful to prune correctly with a sharp pruner or saw, and not too close to the trunk. Cutting the branch collar will damage the tree more. Here is a guide-

https://www.pubs.ext.vt.edu/430/430-457/430-457.html

Yes, you can aerate the root zones by ‘vertically mulching’, drilling holes and filling with compost. You should not fertilize the trees now. If they need fertilizer, do so in the spring. Here is a picture ( see figure 5) of vertical mulching.

https://www.extension.purdue.edu/extmedia/HO/HO-140-W.pdf

Keep trees moist up to when the ground freezes- evergreens must have a moist root zone going into winter, but must not be soggy or drowning- a somewhat tricky situation in your clay soil.

There are some much hardier selections of evergreens for Michigan climate. I include them here should you decide to plant some.

https://www.canr.msu.edu/uploads/files/Alternatives_to_blue_spruce_BertCregg.pdf

And this lists plants that do better in clay soils-

https://extension.umaine.edu/gardening/manual/trees-shrubs-clay-soils/

A certified arborist can do the mulching and fungicide application for you. A certified arborist is a professional who has taken training in care, diseases, pests and passed certification tests. Find certified arborists by zip code here—-

www.treesaregood.org

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