Picea pungens 'Glauca', Colorado Blue Spruce
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Coniferous Trees

Picea pungens 'Glauca'

Colorado Blue Spruce

Pinaceae
Selection from Rocky Mountain populations; species native Montana to New Mexico

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At a Glance

TypeTree
HabitUpright
FoliageEvergreen
Height30–50 feet (9–15 m)
Width10–15 feet (3–4.6 m)
Maturity25 years

Growing Zones

USDA Hardiness Zones

2 - 8
Zone 2Zone 3Zone 4Zone 5Zone 6Zone 7Zone 8
These zones indicate the coldest temperatures this plant can typically survive.
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Frost Tolerancehardy

Key Features

Deer ResistantDrought Tolerant
Native to North America
Maintenancelow

Overview

Picea pungens 'Glauca' is a group designation for selected forms of Colorado spruce with consistently blue-gray to silvery-blue foliage, more intensely glaucous than average seedlings of the species. Trees reach 30–50 feet (9–15 m) tall and 10–15 feet (3–4.6 m) wide; growth rate is 8–12 inches (20–30 cm) per year. The pyramidal crown is dense with stiffly horizontal branches. Needles are 0.75–1.25 inches (19–32 mm) long, rigid, sharply pointed, four-sided, and silvery blue-gray; the glaucous color is caused by a waxy coating on the needle surface. Bark is gray-brown, scaly, becoming furrowed on older trunks. Cones are 2.5–4 inches (6–10 cm) long, cylindrical, light brown. 'Glauca' represents a seed-selection group rather than a clonally propagated cultivar, so foliage color and form vary among individual plants. Rhizosphaera needle cast is a persistent problem in humid climates, progressively defoliating the lower crown.

Native Range

The species Picea pungens is native to the Rocky Mountains of the western United States from southern Montana to New Mexico, in mountain canyons at 6,000–11,000 feet (1,800–3,350 m). The 'Glauca' selection group originated from seed of particularly blue-colored specimens.

Suggested Uses

Planted as a specimen or screen tree in residential and commercial landscapes, spaced 12–15 feet (3.7–4.6 m) from adjacent plants. Because 'Glauca' is seed-propagated, foliage color varies among plants; clonally propagated named cultivars produce more consistent color. The eventual height of 30–50 feet (9–15 m) and lower-branch loss on mature trees limit placement near structures or in confined spaces.

How to Identify

Picea pungens 'Glauca' is identified by rigid, prickly, silvery blue-gray needles 0.75–1.25 inches (19–32 mm) long that radiate from all sides of the stem. The glaucous coating gives the needles a frosted appearance. Distinguished from the species by the more consistently blue-gray foliage; distinguished from named clonal cultivars such as 'Hoopsii' or 'Fat Albert' by the variable blue intensity and form resulting from seed propagation.

Appearance

Size & Dimensions

Height30' - 50'
Width/Spread10' - 15'

Reaches mature size in approximately 25 years

Colors

Flower Colors

yellow
red

Foliage Colors

blue
silver
gray

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~3 weeks
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Spring
Male strobili are reddish-yellow, releasing pollen in April–May. Female cones are 2.5–4 inches (6–10 cm) long, cylindrical, green to purple when young, ripening to light brown. Cones are produced in large numbers on mature trees and may persist on the tree for 2 seasons.

Detailed Descriptions

Flower Description

reddish-yellow (male strobili)

Foliage Description

silvery blue-gray

Growing Conditions

Sun Requirements

Full Sun
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range4.5 - 7.0(Acidic)
357912
Soil Types
loamsandclay
Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

20–30 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Water weekly during the first two growing seasons; established trees tolerate 3–4 weeks without rain and are more drought tolerant than most other cultivated spruces. Rhizosphaera needle cast is the most common and damaging disease in Pacific Northwest conditions; it causes brown needles to drop progressively from the lower crown upward, starting on year-old needles. Cytospora canker causes branch dieback and resinous patches, typically entering through wounds on stressed trees. Spider mites infest foliage in hot, dry summers. Lower branches naturally die as the crown closes on older trees; crowded plantings accelerate this process.

Pruning

No pruning is required to maintain the pyramidal form. Dead branches, including those defoliated by needle cast, can be removed at the trunk. The central leader is dominant and does not require training. Shearing to reduce size exposes old wood that does not regenerate; avoid cutting branches back beyond the current year's foliage.

Maintenance Level

low

⚠️ Toxicity Warning

Non-toxic