2019 Status in Maine: Widespread. Very Invasive.
Description: Extremely shade-tolerant, canopy-height tree, often planted. Cultivars include "Crimson King" which has purple-red color. Leaves: Opposite, 5-lobed with pointed tips but without other teeth. Broken petiole oozes white sap – distinguishes this species from native maples. Winter buds are reddish-green and rounded. Flowers: Tiny, yellow-green, high in canopy, early spring. Fruit: Typical maple samara but with a very wide angle. Bark: Furrowed, dark gray, not shaggy like native maples.
Native range: Europe, Eastern Asia. How arrived in U.S.: As an ornamental and shade tree.
Reproduction: By seeds which are dispersed short distances by wind or small mammals; occasional long-distance transport by water might be possible.
Habitat: Forests, forest edges, open areas. Extremely shade-tolerant, can germinate and compete under a closed canopy.
Similar native species: Norway maple could be mistaken for sugar maple (A. saccharum), but Norway maple has milky petiole sap, furrowed bark, and reddish-green, rounded buds, whereas sugar maple lacks milky sap, has shaggy bark, and has brown, pointed buds.
Similar non-native species: Amur maple (Acer ginnala) is a small tree, has much smaller, narrower leaf shape, and has toothed leaves.
Fact Sheets and Identification Links
- SUNY-ESF, New York, (2:30)
- Vermont Invasives Factsheet for Norway Maple
- Go Botany page for Acer platanoides
Seedlings can be pulled up*; saplings can be pulled with a weed lever or cut, but re-sprouting will occur so follow-up will be necessary. Longevity of seeds is not known. Larger trees can be cut, but will also re-sprout unless the cut stump is immediately treated with concentrated herbicide† (glyphosate or triclopyr). However, this is not effective in early spring due to sap rising. Repeated follow-up cutting can control re-sprouting from cut stumps, but persistence is required, sometimes for many years. Foliar spray can also be effective for seedlings, short saplings, or re-sprouts (glyphosate or triclopyr), as long as you can reach the top of the plant. For stems up to about 4-6" diameter, the basal bark treatment can be effective any time of year(spray lower 18-24" of trunk with triclopyr with penetrating oil). In urban or suburban areas where trees provide valuable shade, a phase-out approach (removing trees gradally over time) with re-planting of native tree species may be advisable.* Correctly dispose of all plant parts↵ † Follow all label directions when using herbicides↵
Control Technique Video Demonstrations
- No appropriate control videos found
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