University of Maryland Extension

Norway Maple

Back to Invasive Plant Photos and Information

Norway Maple
(Acer platanoides)

norway-maple-leaf
Photo: Rob Routledge, Sault College, Bugwood.org

About Norway Maple: An Invasive Plant in Maryland


Life cycle/information: Norway maple (Acer platanoides) is a broadleaf deciduous tree that grows up to 50+ feet in height and produces copious amounts of seeds and dense shade. Native to Eurasia, it was introduced to the United States in the 1750’s. It was used as a street tree due to its fast-growing nature and tolerance of poor soils and air pollution. In some communities, it was planted heavily when American elms were lost to Dutch Elm Disease. The dense shade of these trees reduces light availability for forest understory plants. The dense root system alters nutrient availability and impedes the growth of other species, resulting in lower plant diversity.

Norway-maple-flowers
Norway maple flowers. Photo: Jan Samanek, Phytosanitary Administration, Bugwood.org

Growth habit: Norway maples produce dark green, deciduous leaves with 5-7 sharply pointed lobes. The leaves are opposite of each other along the stem. Greenish-yellow flowers in clusters are produced in April-May. Young bark is smooth. Mature bark is gray-brown with shallow, interlacing ridges and furrows. Fall color is yellow.

Norway maples can be distinguished from other maples by a white milky sap that exudes when a leaf petiole (stem) is detached from the tree.

norway-maple-sap
Norway maple petioles exude white sap. Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Reproduction: Large quantities of paired winged seeds (samaras) are produced. The “wings” of the samara spread widely to nearly 180 degrees. Seeds mature in September-October and often remain on the tree into winter. Spreads to new areas by seeds and vegetative reproduction.

norway-maple-seeds
Norway maple seeds. Photo: Paul Wray, Iowa State University, Bugwood.org  

Conditions that favor growth: Tolerates a wide variety of light and soil conditions. Seedlings establish quickly in deciduous forests.  

norway-maple-infestation
Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

What to plant instead: Red maple (Acer rubrum)                                                                

Controlling Norway Maple

References and Resources

  • Dirr, Michael A. 2009. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses, Sixth Edition.
  • Kaufman, Sylvan Ramsey & Wallace Kaufman. 2007. Invasive Plants: Guide to Identification and the Impacts and Control of Common North American Species.
  • Sarver, Matthew, Amanda Treher, Lenny Wilson, Robert Naczi, Faith B. Keuhn. 2008. Mistaken Identity? Invasive Plants and Their Native Look-alikes.  Delaware Department of Agriculture.
  • Swearingen J., B. Slattery, K. Reshetiloff, and S. Zwicker. 2010. Plant Invaders of Mid-Atlantic Natural Areas, 4th ed. National Park Service and U.S. Fish & Wildlife Service, Washington, DC. 168pp.

Compiled by Christa Carignan, reviewed by Debra Ricigliano, University of Maryland Extension, 10/2018.

Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2019. Web Accessibility