Amur maple (Acer ginnala)

Amur maple leaves are longer than they are wide.

Amur maple was introduced to North American in the 1860s as an ornamental and for wildlife and windbreak plantings. It is tolerant of shade and is often found in disturbed areas, along forest edges, roadsides, in early successional forests and in ornamental landscapes. Amur maple displaces native shrubs and understory trees in open woods, and shades out native grasses and herbaceous plants in savanna habitats.

Description

Appearance

Amur maple is a small tree that can grow up to 20 feet tall with a broad crown. However, it sometimes is seen as a pruned hedge.

Leaves and Stem

Leaves are arranged opposite each other on smooth, lightly colored twigs. Leaves are longer than wide (1-3 inches long) and have double-toothed edges. Leaves have three lobes, with the middle lobe longer than the other two lobes. They turn a brilliant red in autumn.  Amur maple bark is smooth and gray, becoming gray-brown with age. It readily resprouts when cut, so can often be found in both multi-stemmed or single-trunk form.

Flowers

Yellow-white flowers are fragrant and appear in loose clusters in April to June, as young leaves are unfurling.

Seeds

Numerous slightly red inch-long fruit mature in late summer and hang on the tree until late fall. Fruits are double-winged samaras (helicopter seeds), typical of maple trees. Each fruit contains two seeds. Seeds are dispersed mainly by wind, aided by winged samaras.

Roots

Amur maple has a shallow root system made up of thin, branching roots.

Biology

Amur maple is a deciduous tree that can reach heights of 20 feet. It is tolerant of a wide range of soils, but grows best in moist, well-drained soils. It is tolerant of shade and is often found in disturbed areas, along forest edges, roadsides, in early successional forests and in ornamental landscapes.

Origin and Spread

Amur maple is native to Asia, mainly Japan and central and northern China. It was introduced to North American in the 1860s. It is frequently sold commercially as an ornamental and for wildlife and windbreak plantings. A prolific seed producer, Amur maple is becoming invasive in the northern United States. Extensive wild populations have been found in Illinois and Missouri. It resprouts easily from cut stumps.

Amur maple is found in many counties in Minnesota. Refer to EDDMapS Distribution Maps for current distribution.

Don't be fooled by these look-alikes

  • Red maple, Acer rubrum (native) – The middle lobe in Amur maple tends to be more elongated than that of red maple. Amur maple flowers are yellow-white and fragrant, while red maple flowers are reddish and not scented. The fruits of Amur maple hang on the tree into late fall, while red maple drops its seeds much earlier.
 
Regulatory Classification

This species is a Minnesota Department of Agriculture Specially Regulated Plant. Sellers must affix a label that advises buyers to only plant Amur maple and its cultivars in landscapes where the seedlings will be controlled by mowing and other means. Amur maple should be planted at least 100 yards from natural areas.

Threat to Minnesota
  • Amur maple displaces native shrubs and understory trees in open woods, and shades out native grasses and herbaceous plants in savanna habitats.
  • It can produce allelopathic chemicals that limit growth and reproduction of other plants.
What you should do

One way that invasive plant seeds and fragments can spread is in soil.  Sometimes plants are planted purposefully.  You can prevent the spread of invasive plants.

PlayCleanGo: Stop Invasive Species in Your Tracks

  • REMOVE plants, animals & mud from boots, gear, pets & vehicle.
  • CLEAN your gear before entering & leaving the recreation site.
  • STAY on designated roads & trails.
  • PLANT non-invasive species.
Native Substitutes
 
Control Methods

Mechanical control can be done by grubbing out or digging up small infestations. Saplings can be easily pulled by hand or controlled by regular mowing. Prescribed burning will set it back but not eliminate it.

Herbicide control can be done by cutting the stem and applying glyphosate or triclopyr to the cut stump. Oil-based triclopyr ester products can also be sprayed along the base of an un-cut stem, coating all sides of the lower 12-18 inches of the main stem. These are systemic herbicides that are taken up by plants and move within the plant, which can kill leaves, stems, and roots.

Reporting

If you would like to add to the public information about this species you can report occurrences outside of plantings by submitting a report through EDDMapS Midwest. If you see plants being sold without the label required by the  Minnesota Department of Agriculture, you can report that by emailing Arrest The Pest, calling Arrest the Pest (1-888-545-6684), or contacting your local county agricultural inspector.

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