Blue Spruce & Winter Burn

Causes

• As the blue spruce experiences the process of photosynthesis, it releases large amounts of water – sometimes gallons – via the process of transpiration, a form of evaporation. When winter weather causes frozen soil, the tree cannot replenish its water supply, leading to dehydration. Slow-thawing heavy clay worsens this issue. Dehydration, coupled with solar heat, drying winds and even salt spray from roadsides, causes winter burn.

Symptoms

• Winter-burned blue spruce trees exhibit scorched, or rust orange-hued, needle tips or completely browned needles. Some affected trees may have dead terminal buds and twigs. It can be difficult to tell winter burn-affected trees from dying trees. Crack open one of the spruce's low-hanging buds to find the culprit; if the inside of the bud is green and moist, the tree is still living, despite the burn. Winter burn symptoms typically appear in the late winter and early spring seasons.

Prevention

• Though waiting for the needles to regrow is the only proven treatment for winter burn, hydration is key to preventing the issue. Water your blue spruce trees heavily in the autumn season, before the winter freeze occurs. During winter, continue to water the plants as usual, as long as temperatures remain above freezing. Avoid planting your spruces in high-wind areas or construct windbreaks to prevent excessive wind exposure. Protect small trees from winter burn by wrapping them with burlap.

Considerations

• Blue spruce isn't the only tree affected by winter burn; many types of evergreens – especially Sitka spruce and English holly – contend with this issue. Typically, trees affected by winter burn will lose and regrow browned needles over the course of a year or two. In addition to winter burn, common insect pests such as aphids, spider mites, spruce needle miners and yellow-headed spruce sawflies affect the blue spruce. This tree is also susceptible to Cytospora canker, Lirula needle blight and Rhizosphaera needle cast. For trouble-free growing, keep blue spruce in an ideal environment; this tree prefers moist, well-drained, loamy soils with a pH of 6.0 to 7.5 and thrives in full sunlight.