The Norway spruce (Picea abies) is a coniferous evergreen fir tree native to the mountainous regions of Europe and Asia. The species was first described by Linnaeus in 1753 as Pinus abies, but it was later correctly named Picea abies by H. Karsten in 1881. Norway spruce was first planted in the UK for forestry purposes in the 1800s, gaining popularity as a Christmas tree after being introduced by Prince Albert.
Norway spruce grow to an average height of 100 to 200 feet with a spread of roughly 40 feet, though taller specimens have been found in Europe. Its bole, or trunk, is normally straight and does not separate into a fork. Young trees have finely shredded bark, while the bark on mature trees is heavier, scaly and sheds easily. Norway spruce’s deep green needles point forward and their weight causes the branches to droop as the trees age. Cones are brown and narrow and measure from 4 to 6 inches. The tree’s shallow roots grow far from the tree and often over rocks and other obstacles.
Growth of the Norway spruce is slow at first as the tree establishes itself but speeds up as it approaches middle age, or 20 to 60 years. The lower branches fall off as it grows, and its canopy, or top, also thins out and narrows into a less conical shape. While trees in their native range of Europe and Asia often live upwards of 300 years, deterioration of trees in North America and Great Britain begins when they are about 200 years old.
Characteristics
- Growth Habit: The Norway spruce (Picea abies) is a large, pyramidal evergreen tree with a straight trunk. Its branches are slightly upward-curving with pendulous, drooping branchlets, giving the tree a graceful appearance.
- Size: Mature trees typically reach heights of 40–60 meters (130–200 feet) with a spread of 7–10 meters (23–33 feet). In optimal conditions, they can grow even taller.
- Bark: The bark is thin and scaly on young trees, turning darker and fissured with age. It develops a reddish-brown tone, adding to its visual character.
- Growth Rate: Norway spruce grows relatively quickly for a conifer, with an annual growth rate of 1–2 feet (30–60 cm) under favorable conditions.
- Cones: It produces long, cylindrical cones that range from 10–18 cm (4–7 inches) in length. The cones are initially green or reddish and turn brown as they mature, hanging downward from the branches.
- Foliage: The needles are dark green, glossy, and stiff, measuring about 1–2.5 cm (0.4–1 inch) in length. They are arranged spirally around the twigs and emit a slightly resinous aroma when crushed.
- Lifespan: Norway spruces are long-lived trees, with a typical lifespan of 200–300 years. Some specimens in favorable conditions have been known to live for over 500 years.
- Root System: This species has a shallow yet widespread root system, which provides stability but makes it vulnerable to windthrow in shallow or wet soils.
- Climate Adaptation: It thrives in cool, temperate climates and prefers moist, well-drained soils. Norway spruce is tolerant of various soil types but performs best in slightly acidic conditions.
- USDA Hardiness Zones: The Norway spruce thrives in USDA Hardiness Zones 2–7, making it highly adaptable to a wide range of climates, from very cold northern regions to moderate temperate areas. It is especially valued for its ability to withstand harsh winters.
Norway Spruce Distribution
The Norway Spruce (Picea abies) has a wide natural distribution in Europe, extending from Norway in the northwest to Poland in the east. Its eastern limit is usually given as the Ural Mountains, although trees with some Siberian spruce characters can be found as far west as northern Finland and northeast Norway. The Norway Spruce also grows in the mountains of central Europe, southwest to the western end of the Alps, and southeast in the Carpathians and Balkans to the extreme north of Greece. It thrives in cool, temperate climates and is found in the arctic region, just north of 70° N in Norway.
In North America, the Norway Spruce has been widely planted in the northeastern, Pacific Coast, and Rocky Mountain states, as well as in southeastern Canada. It has naturalized in some parts of North America, with populations occurring from Connecticut to Michigan, and likely elsewhere.
The Norway Spruce has been introduced to many parts of the world for its wood and as a Christmas tree species. It is the species used as the main Christmas tree in several countries around the world. Every Christmas, the Norwegian capital city, Oslo, provides Norway spruces to the cities of London (the Trafalgar Square Christmas tree), Edinburgh, and Washington, D.C., as a sign of gratitude for the aid these countries gave during the Second World War.
In the northern US and Canada, Norway spruce is reported as invasive in some locations; however, it does not pose a problem in Zone 6 and up as the seeds have a significantly reduced germination rate in areas with hot, humid summers.
The Norway spruce tolerates acidic soils well, but does not do well on dry or deficient soils. From 1928 until the 1960s it was planted on surface mine spoils in Indiana
Cultivation of a Norway Spruce
- Site Selection:
Choose a location with full sun exposure, as the Norway spruce thrives in direct sunlight. It can tolerate partial shade but performs best in bright, open areas. - Soil Requirements:
Plant in well-drained, fertile soil. Although the tree is adaptable to various soil types, including sandy, loamy, and clay soils, it prefers slightly acidic to neutral pH levels for optimal growth. - Planting:
Dig a hole twice as wide as the root ball and as deep as its height. Position the tree so the root collar (where the roots meet the trunk) is at ground level, then backfill the hole with a mix of native soil and organic matter. - Watering:
Water young trees regularly, especially during the first two years, to establish a strong root system. Mature trees are moderately drought-tolerant but benefit from occasional deep watering during prolonged dry periods. - Mulching:
Apply a 2–3 inch layer of mulch around the base to retain soil moisture, regulate temperature, and suppress weed growth. Keep the mulch a few inches away from the trunk to prevent rot. - Fertilization:
Fertilize annually in early spring using a balanced, slow-release fertilizer formulated for evergreens. This promotes healthy growth and vibrant foliage. - Pruning:
Minimal pruning is needed. Remove dead, damaged, or diseased branches as needed, and prune lightly to maintain shape. Perform pruning in late winter or early spring before new growth begins. - Spacing:
Space trees 12–15 feet apart when planting multiple specimens. This allows adequate airflow and room for the tree to develop its natural form, minimizing the risk of disease. - Pest and Disease Management:
Monitor for common pests like spruce budworms, aphids, and bark beetles. Maintain tree health through proper care to reduce susceptibility to pests and diseases like root rot and needle cast. - Protection from Wind:
Although Norway spruce is wind-resistant once established, young trees with shallow roots may need protection in windy areas. Using stakes during the initial years can help stabilize the tree until it develops a stronger root system.
Reproduction
The Norway spruce, like other pines and firs, reproduces by means of seeds that form inside cones during the summer and early fall. It is classified as monoecious because both male and female reproductive parts are found on the same tree. Reproduction starts taking place when the trees are 30 to 40 years old, as wind-borne pollen from the male flowers fertilize female flowers that subsequently develop into cones, which sometimes drop some of their seeds before falling from the trees. Norway spruce seeds germinate readily and seedlings develop quickly. New sprouts never emerge from the stumps or roots.
Spruce cuttings root well in sand or a mixture of 1 part vermiculite and 1 part perlite. These materials are well-draining and provide the needed support for cuttings to stay upright. Plastic trays or flats are suitable for a large number of cuttings with their large, open surfaces. Plastic 4-inch pots are best for rooting individual cuttings. Containers must have drainage holes in the bottom to allow excess water to escape, preventing the development of mold. Plant cuttings by simply pushing the bottom, needleless portion straight down into the sand. Plant multiple cuttings 3 inches apart so they do not touch.
Uses
- Timber: It is a timber tree of major economic importance throughout the cool temperate areas of Europe.
- Christmas Trees: Despite its poor suitability for this purpose, it is commonly used as a Christmas tree in several countries.
- Mycorrhizal Roots: Phenolic compounds such as p-hydroxybenzoic acid glucoside, picein, piceatannol, and astringin are found in mycorrhizal and non-mycorrhizal roots of Norway spruces.
- Genetic Research: It was the first gymnosperm to have its genome sequenced, providing valuable insights into its genetic makeup and evolutionary history.
Challenges
- Forest Decline: Norway spruce is experiencing a specific set of symptoms (“Waldsterben”) which are also showing up in forest trees in the United States, including red spruce (Picea rubens). These symptoms include needle chlorosis combined with magnesium deficiency and thinning of the crown, often attributed to air pollution and acidified soils.
- Disease and Pests: The tree is susceptible to Cytospora canker and Rhizosphaera needle cast. Bagworms and spider mites can also be problematic.
Norway Spruce Cultivars
- Bird’s Nest Norway spruce (Picea abies ‘Nidiformis’): This cultivar is much smaller than the species, growing 3 to 6 feet high and wide. It is a dwarf, evergreen shrub with stiff, prickly, green to bluish-green needles and a neat, dense, compact shape. The outward spreading branches create a slight depression in the center, giving rise to its name.
- Acrocona Norway spruce (Picea abies ‘Acrocona’): This cultivar has a broad-spreading pyramidal form and may reach up to 20 feet in height. It produces bright red female cones at the ends of its branches.
- Cupressina Norway spruce (Picea abies ‘Cupressina’): This narrow cultivar grows 25 to 30 feet high and 6 feet wide, making it more tolerant of heavy snow loads.
- Weeping Norway Spruce (Picea abies ‘Pendula’): This cultivar grows 12 to 15 feet high and wide, with a weeping habit. It is often used as a specimen plant in a mixed border.
- Gold Drift Weeping Norway Spruce (Picea abies ‘Gold Drift’): This golden weeping variety has needles that are gold where touched by the sun and a light lime green color in the shade.
- Dwarf Norway Spruce (Picea abies ‘Pumila’): This dwarf cultivar grows 3 to 4 feet high and 4 to 5 feet wide, with a more rounded form than the Bird’s Nest Spruce.
- Reflexa Norway Spruce (Picea abies ‘Reflexa’): This cultivar is a weeping form of Norway spruce, though it is not as widely recognized as ‘Pendula’.
- Nidiformis Norway Spruce (Picea abies ‘Nidiformis’): Another name for the Bird’s Nest Norway spruce, this cultivar is known for its compact, bird’s nest shape.
- Cupressina Norway Spruce (Picea abies ‘Cupressina’): This cultivar is noted for its narrow form and tolerance to heavy snow loads, similar to the description of ‘Cupressina’ above.
- Pendula Norway Spruce (Picea abies ‘Pendula’): This cultivar is a weeping form of Norway spruce, often used as a specimen plant in gardens.