Weird Spruce Growths

Coolie gall on Picea pungens @ColoCollege 2003july6 LAH 096“My spruce tree has brown things all over it! Is it sick?” The caller was quite anxious. He had a beautiful Colorado Blue Spruce growing in his yard, and now it had some sort of weird alien growths at the ends of all the branches. Was it going to die?

Over the years that I volunteered at the master gardener help desk, we would often get calls like this. No, the caller’s tree wasn’t sick, not exactly. Those prickly, cucumber-shaped growths that show up on spruces from time to time are actually galls caused by an insect. They might look peculiar, but they weren’t going to cause significant harm to his spruce.

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