Norway maple (Acer platanoides) is a species of maple native to eastern and central Europe, and western Asia, from Spain east to Russia, north to southern Scandinavia, and southeast to northern Iran. It was introduced to North America in the mid-1700s as a shade tree. Norway maple is a member of the family Sapindaceae and is a part of the section Platanoidea Pax, which is characterized by flattened, disc-shaped seeds and the shoots and leaves containing milky sap.
In its native range, the Norway Maple can live up to 250 years, but in North America, it may only survive for about 60 years. It is a dioecious species (has separate male and female trees). The tree has large leaves, which turn yellow or orange in the fall. The bark is gray and furrowed on mature trees. The Norway maple is distinguished by its larger leaves with pointed, not blunt, lobes, and from the other species by the presence of one or more teeth on all of the lobes
The first documented import of Norway maple into North America happened around 1756 when John Bartram of Philadelphia received seedlings from England and began cultivating the species at his garden and nursery. This was significant as Bartram owned one of the only two tree nurseries in the United States at the time, the other being Prince’s Nursery in Flushing, New York. By 1762, the Norway maple was offered in an early seed catalog, marking its official entry into the American nursery trade.
In North America, Norway maples are considered invasive species in some regions. They can outcompete native trees and shrubs for light, water, and nutrients. They also produce a large number of seeds, which can easily spread long distances by wind.
Identifying Physical Characteristics
- The Norway Maple is a deciduous tree that can grow up to 20–30 m (65–100 ft) tall.
- It has a dense, rounded, and symmetrical crown.
- The branches grow outwards and often droop slightly at the tips.
- The twigs are slender and brown with tiny white spots.
- The bark is grey with fine ridges, and the twigs are slender and brown with tiny white spots.
- The leaves are arranged opposite, as in the sycamore maple, and the leaf stalk can grow up to 20 centimeters long.
- The leaf top has a dark green, glossy color, and the interior of the petiole contains a milky liquid.
- The leaves are dark green and typically turn pale yellow in the fall, but there is a popular cultivar that has deep reddish-purple fall foliage.
- The tree produces bright green flowers that grow in clusters of up to 30.
- The flowers are already visible long before the foliage emergence and contain a lot of nectar.
- The angle of the seeds is wider in Norway maple.
- Each fruit (samara) consists of two winged seeds joined together, resembling a helicopter blade.
- The “wings” of the samara spread widely to nearly 180 degrees, a characteristic that distinguishes Norway maple from other maple species.
- Norway maple can be distinguished from other maple species by the milky white fluid that oozes when the stem of a leaf is broken.
- The bark of the maple tree is characterized by prominent furrows, the bark can show a light gray to greenish-gray color.
- The bark of the maple is traversed by small, elongated grooves and has the property not to peel off.
Habitat and Growing Conditions
- The tree has a high tolerance to pollution and is adaptable to many soils including clay, sand, or acidic conditions.
- Has a moderate water need and prefers full sun to partial shade. It is hardy to USDA zones 4 to 7.
- It is widely planted as an ornamental tree in parks and gardens due to its tall trunk and tolerance of compacted soils, shade, and pollution.
- The tree is also capable of growing in low lighting conditions within a forest canopy, leafs out earlier than most North American maple species, and its growing season tends to run longer.
Interesting Facts about Norway maple
- Norway maple is the national tree of Norway.
- The Norway maple has been used as a boulevard tree extensively in the urban canopy around Minnesota.
- In its native range, the Norway Maple can live up to 250 years, but in North America, it may only survive for about 60 years.
- They produce a large number of winged seeds that can easily travel long distances by wind, contributing to their invasive potential.
- Norway maple is considered an invasive species in some areas, as it can out-compete sugar maple due to its shade tolerance and form a dense canopy that reduces wildflower diversity.
- As with most maples, Norway maple is normally dioecious (separate male and female trees), occasionally monoecious, and trees may change gender from year to year.
- Flowering and seed production begins at ten years of age, however large quantities of seeds are not produced until the tree is 20.
- The leaves are a favorite food source for many caterpillar species.
- The wood is used in some high-quality instruments, with Stradivarius violins being a famous example.
- Unlike some maples, Norway maples tolerate partial shade and can still thrive.
- These trees grow relatively quickly, providing shade sooner than some other species.
- They are tolerant of air pollution and de-icing salt, making them suitable for urban areas (although planting native alternatives is preferable due to their invasive nature).
- There are many cultivars available with variations in leaf size, shape, and color.
- Norway maple should be planted at least 100 yards from natural areas.
- Their roots tend to be quite shallow and thereby they easily out-compete nearby plants for nutrient uptake
Norway Maple vs Sugar Maple
- The sugar maple usually has a brighter orange autumn color, where the Norway maple is usually yellow, although some of the red-leaved cultivars appear more orange.
- The sugar maple has clear sap in the petiole (leaf stem); Norway maple petioles have white sap.
- The tips of the points on Norway maple leaves reduce to a fine “hair”, while the tips of the points on sugar maple leaves are, on close inspection, rounded.
- On mature trees, sugar maple bark is more shaggy, while Norway maple bark has small, often criss-crossing grooves.
- While the shape and angle of leaf lobes vary somewhat within all maple species, the leaf lobes of Norway maple tend to have a more triangular (acuminate) shape, in contrast to the more finely toothed lobes of sugar maples, that narrow towards the base.
- Norway maple seeds are flattened, while those of sugar maple are globose.
- The “wings” of the samara of Norway maple spread widely to nearly 180 degrees whereas those of Sugar maple are are at 90 degrees to each other.