The Norway spruce (Picea abies) is a species of spruce native to Europe. It is also commonly referred to as the European Spruce. The Norway spruce is a large evergreen coniferous tree which grows approximately 115–180 ft tall. The shoots are orange-brown and glabrous (hairless). The leaves are needle-like, quadrangular in cross-section (not flattened), and dark green on all four sides with inconspicuous stomatal lines. The cones are the longest of any spruce, and have blunt triangular-pointed scale tips. They are green or reddish, maturing brown 5–7 months after pollination.
The Norway spruce hybridises extensively with the Siberian Spruce, therefore pure specimens are rare. Hybrids are commonly known as Norwegian Spruce, which should not be confused with the pure species that is the Norway spruce. In North America, the Norway spruce is widely planted, specifically in the northeastern, Pacific Coast, and Rocky Mountain states, as well as in southeastern Canada. There are naturalized populations of The Norway spruce occurring from Connecticut to Michigan, and it is probable that they occur elsewhere. The tallest measured Norway spruce is 207 ft tall, is located in Perucica Virgin Forest, Sutjeska National Park, Bosnia-Herzegovina.
Seasonal information: The Norway spruce can grow 2-3+ feet per year their first 25 years under good conditions; in heavy or poor soils they may average 1 foot per year. Soil, moisture, and adequate sunshine are everything to a plant and its growth rate. On a perfect weather year, and no competition from grass or weeds, one might see over 6 ft of growth in one year!
Location: Choose a place to plant the Norway spruce: don’t plant it too close to sidewalks, buildings, or street right-of-ways. It’s best to plant the tree as soon as you bring it home from the nursery, but it’s important to avoid planting the tree during extremely dry weather and to give it at least six weeks to develop before the first frost of the season. If you need to wait to plant the tree, keep the roots constantly moist.
Planting instructions: Dig a large hole, not too deep, but at least twice as wide as the size of the Norway spruce root ball. This will give the roots plenty of room to spread. If the tree is in a plastic pot, cut the pot away carefully, but do not pull it out by the trunk. If the roots are wrapped in burlap, the burlap can be left in place. Just fold the top of the burlap down and away from the trunk and tuck it under the tree. Dampen the roots in preparation for planting, and set the root ball into the hole, being sure the trunk is straight. Refill the hole with soil, tamping it down around the root system as you go–otherwise, air pockets can develop, which can dry out the roots. The trunk should be above ground, but all of the roots should be covered.
Watering: The Norway spruce tolerates acidic soils well, but does not do well on dry or deficient soils. During times of drought, additional watering may be needed and should be planted six weeks before the first frost.
Fertilization: Feed Norway spruce mild, slow-acting fertilizer tabs for the initial growing season and save stronger fertilizers for when the tree is established. Once the tree is established, feed it twice a month during early spring and once a month during the summer months. Do not feed the tree just before it goes into dormancy for the winter.
Weed Control: Control weeds under the Norway spruce until the tree is well-established, so that the weeds do not compete with the young tree for water and nutrients. Once you have removed the weeds, add a heavy layer of mulch to help keep them under control and to retain moisture.
Pests and Disease: In areas of deer population, protect your spruce by using a cage during the first few months of plantation. Please note, the Norway spruce cone scales are used as food by the caterpillars of the tortrix moth Cydia illutana, while C. duplicana feeds on the bark around injuries or canker; so be sure to check your spruce regularly for signs of pests.
Pruning: Prune Norway spruce in the late winter or early spring. For young trees, follow branch tips back until you find two branches growing to either side. Snip off the center branch growth. Doing this will encourage the side branches that remain to grow faster and to make the tree bushier. Cut the lowest rung of branches on the tree to force more height. For a six- to seven-year-old Norway spruce, remove three rungs of lower branches to reveal a foot of the trunk. This age for Norway spruce is excellent for a small Christmas tree, indoors or out. Prune whole, lower branches of mature Norway spruce if they are obstructing pedestrian or car traffic. Prune higher than that only if you see dead or dying branches, or if the tree is touching siding or your roof. Do not prune parts of branches, because this will cause browning and needle die-off in the remaining part of the branch.
Pollination: The adult Norway spruce is monoecious, which means that has both male and female parts. This means that it can pollinate itself—the male flowers can pollinate the female flowers. The Norway spruce produces seven-inch cones that are first purplish-green and then brown. The cones release their seeds, which fall down to the ground or are carried away by animals or birds.