Colorado Blue Spruce 'Kaibab'

Colorado Blue Spruce (Picea pungens) 'Kaibab' is the silvery-blue spruce you picture when you picture a spruce. A neat narrow pyramid, horizontal tiers of branches sweeping almost to the ground, and stiff, prickly, four-sided needles up to 4 cm long that hold their frosty blue tone all year round.

This is a tree for space: mature specimens reach 9-18 m tall and 3-6 m wide, so it is planted as a lawn specimen, in groups, or in shelter belts in large gardens and parks. Open sun gives the best blue; in shade the tone dulls. Hardy to -45 °C (USDA zone 2) and almost maintenance-free.

Key characteristics:

• What makes it special: It shrugs off wind and city dust, so it keeps its looks even along busy streets and on open, exposed sites.
• Dimensions: In time it grows into a real giant: 9-18 m tall and 3-6 m wide at maturity.
• Hardiness: Overwinters with no cover at all - hardy to -45 °C (USDA zone 2).
• Light: Happiest in full sun; it takes light shade, though the silvery-blue tone of the needles is at its best in the open.
• Soil: Likes slightly acidic, moderately moist, well-drained soil of average fertility, and grows best on rich, moist substrates.
• Watering: Water moderately and regularly - in the first years after planting the soil should not be left to dry out.
• Care: Care is minimal: no pruning needed, just keep an eye out for needle cast, cytospora, aphids and spider mite.
• Landscape use: A striking specimen and vertical accent in large gardens and parks, and a dependable choice for windbreak planting.
• Origin: This is not a clonal cultivar but a seed provenance from the Kaibab Plateau in Arizona, so the intensity of the blue can vary from plant to plant.