Norway maple

Norway maple is common throughout the U.S. and Canadian portions of the Great Lakes region. Nationally, it is most frequently reported as invasive in New England and the Mid-Atlantic. USDA reports Norway maple as being hardy to a minimum temperature of -28^oF (Zone 4a), though certain cultivated varieties are advertised as being hardy to Zone 3. Particularly dense infestations can be expected in areas close to where the species has been or still is popular as a street or yard tree. 

Additional invasive species distribution data for specific Great Lakes jurisdictions is available from:

• Midwest Invasive Species Information Network (Michigan)
• iMapInvasives (New York and Pennsylvania)
• EDDMapS Ontario

Norway maple seed is distributed by wind. Research has shown that the normal maximum range of Norway maple seed travel is 165 feet from the parent (Matlack 1987). This is a relatively low dispersal distance compared to species whose seeds are bird or wildlife dispersed. Through movement of seed from successive generations, Norway maple can eventually invade interior areas. 

Norway maple invades open and forested areas, including old fields, open woods, forest edges, forest interiors, and transport and utility right of ways. Although it prefers full sun, seedlings can germinate and grow to maturity in shaded conditions (Munger 2003). It is most prevalent at disturbed sites such as abandoned residential, commercial and agricultural land, and highly fragmented and otherwise disturbed forests. However, studies have shown that Norway maple seedlings can establish and dominate in high-quality forest interiors (Webster et al. 2005).

Norway maple can out-compete native trees and suppress the growth of herbaceous plants and native understory shrubs in forests by establishing dense shade. 

Norway maple was introduced to the U.S. during the late 18th century. It was widely planted as a street tree starting in the mid-20th century to replace elms destroyed by Dutch elm disease. It remains a popular street and yard tree due to its toughness and ability to thrive adverse conditions, its relatively fast growth, and ability to establish dense shade.

Research conducted at Penn State University indicates that certain Norway maple cultivars produce significantly less seed than the species and other seedy cultivars (Conklin and Sellmer 2009). Some limitations of the study are that only six cultivars were evaluated (of over 20 cultivars readily in trade), and that the observation period was three years, which is relatively short compared to the total reproductive life of a tree. Population modeling indicates that for long-lived species, such as trees and shrubs, even relatively low seed producing types can contribute to invasive populations (Knight et al. 2011).

Please see our Landscape Alternatives pages for more information about how the WIGL Collaborative selected alternatives.

~ = trait is somewhat present but not as pronounced as in check-marked examples

^a Freeman  maple is a hybrid of two native maple species (silver and red). It grows faster than red maple and has better branch structure than silver maple.
^b The species is too large for most urban areas, but narrow cultivars may be suitable.

Green = native to part of the Great Lakes Basin
Blue = not native but not invasive

The WIGL Collaborative’s decision trees are designed to help site users, who are perhaps newly discovering that plants that are part of their home landscaping are invasive, prioritize which species should be removed first based on risk to the surrounding environment, economy, and occasionally, to human health. In a perfect world, everybody would remove all invasive plants from their landscaping right away, but in reality, removing mature woody plants involve a hefty investment of time and/or money. These diagrams can help people with multiple woody invasives in their landscaping prioritize to get the most benefit for their efforts.

To learn more about the methodology and information used to develop the decision trees and for helpful hints on how to answer the questions, please see the full report here (PDF).

The following is a brief overview of management techniques shows to be effective on Norway maple. For more detailed information on how to use these techniques, visit our Management and Control page. For local assistance managing woody invasive species, please get in touch with a cooperative invasive species management group or a university extension program.

Timing and spread concerns: Early detection is an advantage in managing any invasive species. Whenever possible, plants should be controlled before they begin producing seed at around 10 years of age. If control is undertaken when seed is present, it is best not to remove plant material from the site to avoid spreading seed. 

Physical control: Seedlings are easily hand-pulled from moist soil; larger saplings can be dug or pulled using equipment. Cutting or mowing may be effective. Although Norway maple can resprout from cut stumps, it seems to do so less aggressively than many invasive trees and shrubs. The incidence of regrowth also seems to depend on age, with mature trees regrowing less readily after felling than seedlings and saplings (Munger 2003).  Mature trees can also be girdled in early summer by removing a four inch strip of bark and cambium from the whole circumference of the trunk. All cut and girdled trees should be monitored for regrowth and treated with herbicide if needed.

Chemical and combined approaches: Cut stump, stem-injection, and basal bark herbicide treatment are all effective and can be applied during most times of the year outside of early spring when sap is flowing upward. Herbicide should be selected carefully based on site conditions, and label directions read and followed carefully. 

With any treatment it will be necessary to monitor for and treat regrowth and new seedlings in subsequent years.

• Conklin, JR and JC Sellmer. 2009. Flower and seed production of Norway maple cultivars. HortTechnology. 19(1): 91-5.
• Dirr, MA. 1998. Acer platanoides. In: Manual of Woody Landscape Plants, Fifth Edition. Champlain, IL: Stipes Publishing, p40-43.
• Knight, TM, Havens, K, and P Vitt. 2011. Will the use of less fecund cultivars reduce the invasiveness of perennial plants? BioScience. 61(10): 816-22.
• Marlack, GR. 1987. Diaspore size, shape, and fall behavior in wind-dispersed plant species. American Journal of Botany. 74(8): 1150-60.
• Munger, GT. 2003. Acer platanoides. In: Fire Effects Information System (Online). U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. 
• Webster, CR, Nelson, K, and SR Wangen. 2005. Stand dynamics of an insular population of an invasive tree: Acer platanoides. Forest Ecology and Management. 208(1-3): 85-99.
• Author: Clair Ryan, Coordinator, Midwest Invasive Plant Network