MANHATTAN, Kan. – Blue spruce samples (from Colorado-type trees to dwarf Alberta spruce shrubs) with purplish needles have been arriving this spring at Kansas State University’s Plant Disease Diagnostic Lab. Owners are reporting needle drop, branch dieback and the occasional tree death.

"Insects and diseases both can cause these kinds of symptoms. But we’re mostly seeing injury that is a direct result of last summer’s drought," said Ned Tisserat, K-State Research and Extension plant pathologist.

Blue spruces are an "iffy" landscape choice in Kansas, he explained, because they aren’t well adapted to either extended drought or extremely high temperatures.

Spruces showing less severe damage – particularly if just on one side – are usually victims of winterburn.

Last year’s winter wasn’t unusually cold, Tisserat said. But it did arrive before many landscape plants had "winterized." It also brought a stressing mix of down-and-up temperatures.

Most of these spruces should survive, he said.

But, they’ll need special care through the coming growing season because they’re still under stress. Tisserat recommended:

Unless sure they’re dead, wait until after bud break to prune bare-looking twigs. Although they have no needles, some twigs may have healthy buds.

Do not use a broadleaf weed killer near the root zone.

Mulch young plants to reduce soil’s summer temperature rise and moisture loss.

Keep the entire root zone moist (not wet) during droughty conditions.

Carefully monitor for mite infestations, which often result in "hot spots" where needles discolor and drop.

"Those guidelines are useful in good years and bad, however, because almost any year in Kansas is stressful to spruces," the plant pathologist said.