Colorado Blue Spruce
Picea pungens
Overview
Popular ornamental evergreen valued for blue color, though native to Rocky Mountains, not Eastern Ontario
Identification
Leaves
Stiff, sharp, four-sided needles ranging from green to silvery-blue. Very sharp to touch. Blue color is waxy coating.
Bark
Gray-brown bark with irregular scaly plates, relatively thin throughout life.
Flowers
Male cones are yellow, female cones are reddish-purple, appearing in spring.
Fruit
Cylindrical cones 2-4 inches long with papery scales, hanging from branches when mature.
🦆 Valuable wildlife food source
Growing Conditions
Climate
Adapted to cold climates but struggles with Eastern Ontario humidity and heat. Better suited to drier climates
Hardiness Zones: 3, 4a, 4b, 5a, 5b
Light Requirements
Soil
Moisture: moist
Drainage: well-drained
pH Range: 6 - 7.5
Tolerance
Care & Maintenance
Pruning
Best Season: February-April
Frequency: Minimal pruning needed
- Remove dead branches as needed
- Prune in February-April if shaping desired
- Lower branches naturally die as tree matures
Avoid: No specific restrictions
Watering
Establishment: Regular watering for first 2-3 years
Mature: Drought tolerant once established
Seasonal Care Timeline
Spring
- Monitor for spider mites
- Check for winter damage
- New growth emergence
Summer
- Heat and humidity stress in Eastern Ontario
- Watch for Cytospora canker symptoms
- Supplemental watering during drought
Fall
- Spider mites active again
- Assess tree health
- Prepare for winter
Winter
- Heavy snow load on dense branches
- Salt damage from roads
- Blue color most prominent
Common Issues
Cytospora Canker
HighFungal disease causing branch dieback
Symptoms: Needle browning and drop, White resin on branches, Branch dieback from bottom up
Treatment: Prune infected branches, improve tree vigor
Prevention: Maintain tree health, avoid stress, adequate watering
Professional arborist recommended
Rhizosphaera Needle Cast
ModerateFungal disease causing needle browning and drop
Symptoms: Purple-brown needles, Needle drop from inside out, Thinning appearance
Treatment: Fungicide applications in spring, prune dead branches
Prevention: Ensure good air circulation, avoid overhead watering
Spruce Spider Mite
ModerateTiny mites that suck sap from needles
Symptoms: Stippled needles, Webbing, Needle browning, Needle drop
Treatment: Horticultural oil spray, insecticidal soap
Prevention: Maintain tree vigor, water during drought
Quick Facts
When to Call an Arborist
Recommended inspection: Annual inspection recommended
- •Lower branch dieback
- •White resin on branches
- •Extensive needle browning
- •Decline in overall vigor
- •Heavy pest infestation
Free consultation for Belleville residents
Recommended Services
Based on Colorado Blue Spruce characteristics