Blue Spruce (Pungens)

The Blue Spruce (Pungens) is generally described as a perennial tree. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The greatest bloom is usually observed in the late spring, with fruit and seed production starting in the summer and continuing until fall. Leaves are retained year to year. The Blue Spruce (Pungens) has a long life span relative to most other plant species and a slow growth rate. At maturity, the typical Blue Spruce (Pungens) will reach up to 100 feet high, with a maximum height at 20 years of 20 feet.

The Blue Spruce (Pungens) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, cuttings, seed. It has a moderate ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -38°F. has medium tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Blue spruce has been little used for lumber or wood products because it is rarely abundant in nature and the wood is brittle and often full of knots. It sometimes is cut with Engelmann spruce. Because of its cold hardiness, symmetrical pyramidal form, and waxy, blue-hued foliage, blue spruce is widely planted in ornamental and general landscape settings. Numerous horticultural cultivars have been developed, based on needle color and crown form. It is used considerably for Christmas trees and blue spruce plantations have been established in the northeastern US – these probably the source of

escapes reported for several states far from its native range (Maine, Massachusetts, New York, Pennsylvania, Maryland). Blue spruce is the state tree of Colorado and of Utah.

General Characteristics

General: Pine Family (Pinaceae). Native trees growing to 50 meters tall, the crown long-conic; branches whorled, ascending to slightly to strongly drooping; twigs not pendent, stout, yellow-brown, usually without hair; many small twigs produced on the main trunk and between the main whorls of branches; bark relatively thick, gray-brown, breaking into furrows and rounded ridges, only slightly scaly. Needles are evergreen, borne singly and at right angles from all sides of the twig, 1.6-3 cm long, 4-angled, stiff and sharply spine-tipped, silvery to blue-green. Seed cones are green or violet, ripening pale buff, (5) 6-11 (12) cm long, ellipsoid, pendent, the scales elliptic to diamond-shaped, widest below middle, stiff at the base, the tip flexible, unevenly toothed, and extending 8-10 mm beyond seed-wing impression. The common name is based upon the blue foliage color of some races.

Variation within the species: trees with similar color tend to occur in small, local populations, suggesting that color traits are under genetic control. The color variation does not conform to a clinal pattern. Most other variable features in blue spruce (e.g., physiology, early survival, growth rate) similarly do not follow geographical parameters; date of bud set follows a local altitudinal pattern.

Besides features of habit, leaf color, and habitat, blue spruce is distinguished from Engelmann spruce by its cones and cone scales that average larger in size, but these characteristics are often partially or completely overlapping. Blue spruce also differs in its glabrous twigs.

Required Growing Conditions

The native range of blue spruce is the central and southern Rocky Mountains of the USA – in Idaho, Wyoming, Utah, Colorado, New Mexico and Arizona. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Adaptation Blue spruce commonly occurs on stream banks in moist canyon bottoms (hence one of its common names, water spruce) but may grow on gentle to steep mountain slopes in Douglas fir or spruce-fir woods up to timberline; at 1800-3000 meters elevation in mid-montane forests. It often grows with subalpine fir, white fir, and Engelmann spruce. It is cultivated on a wide variety of soils, except those that are very moist.

Cultivation and Care

Blue spruce begins to produce seed at about 20 years; maximum seed production occurs between 50-150 years. Good cone years occur at intervals of 2-3 years. Seed germination is mostly confined to exposed mineral soil with side shade and overhead light, but natural reproduction is scanty, probably because the light seeds are prevented from coming into contact with mineral soil by the dense herbage, grass, or other ground-cover vegetation that is usually abundant in the habitat of the species. Seedling establishment is probably benefited by moisture availability and shading, which prolong snow and soil moisture in late spring.

Blue spruce is a slow-growing tree and some individuals have been reported to live for more than 600 years. Reproduction by layering has not been reported for this species.

General Upkeep and Control

Western spruce budworm larvae feed on old needles in late April then mine developing buds and defoliate new tree growth. Heavy repeated attacks kill the tree.

Plant Basics
Category
Growth Rate Slow
General Type Tree
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Long
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Late Spring
Displays Fall Colors No
Shape/Growth Form Single Stem
Drought Tolerance Medium
Shade Tolerance Intermediate
Height When Mature 100
Vegetative Spread None
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance High
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Cuttings, Seed
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature -38
Soil Depth for Roots 18
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5.5–7.8 pH
Precipitation Range 20–20 inches/yr
Planting Density 300–700 indiv./acre
Soil Textures Coarse, Medium
Soil Depth for Roots 18
Minimum Frost-Free Days 120 day(s)
Salinity Tolerance Medium
CaCO3 Tolerance High
Sustainability & Use
Leaf Retention Yes
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA