Colorado Blue Spruce
Picea pungens
ConiferAbout Colorado Blue Spruce
Colorado Blue Spruce is a popular ornamental conifer known for its striking silvery-blue needles and dense, pyramidal form. Native to the Rocky Mountains, it is widely planted as a specimen tree and windbreak across North America. It is the state tree of Colorado and Utah.
Quick Facts
How to Identify Colorado Blue Spruce
- Stiff, sharp, square-in-cross-section needles with a silvery-blue color
- Dense, symmetrical, pyramidal form
- Gray-brown, scaly bark
- Pendulous, tan-brown cones 2-4 inches long
- Branches extend to the ground when grown in the open
Care Guide
- Water deeply but infrequently once established
- Avoid planting in hot, humid climates where disease pressure is high
- Do not prune the central leader; only remove dead or diseased branches
- Watch for Rhizosphaera needle cast and cytospora canker
- Provide good air circulation to reduce fungal problems
Known Issues (4)
Bagworm
MODERATEA moth whose larvae construct distinctive spindle-shaped bags from silk and foliage fragments. They feed on over 100 species of trees and shrubs, with conifers being most vulnerable since they cannot regrow lost foliage as readily.
Affecting 28 regions
Rhizosphaera Needlecast
HIGHA common fungal disease of spruce trees, especially Colorado blue spruce, throughout the Midwest and Northeast. The fungus infects current-year needles through stomata, causing them to turn purple-brown and drop prematurely. Inner and lower branches are affected first because humidity is higher there, and the disease progresses upward and outward over successive years. Severely affected trees may retain only the current year's needles at branch tips.
Affecting 25 regions
Stigmina/SNEED Needlecast
HIGHA fungal disease of spruce very similar in appearance to Rhizosphaera needlecast but caused by a different fungus. Often occurs alongside Rhizosphaera. It has become increasingly recognized as a major cause of spruce needle loss, particularly on Colorado blue spruce. Diagnosis requires microscopic examination to distinguish from Rhizosphaera.
Affecting 20 regions
Cytospora Canker
HIGHA common fungal disease of spruce and other conifers that causes branch dieback, typically starting from the lowest branches and progressing upward. Colorado blue spruce and Norway spruce are especially susceptible. The fungus enters through wounds or stressed tissue. White resin bleeding on bark is a hallmark sign. Stressed trees are most vulnerable.
Affecting 25 regions