Acer platanoides aka Norway Maple

Norway maple, Acer platanoides, is a deciduous tree in the soapberry family, Sapindaceae. Its native range runs from northern Europe through the Caucasus to Central Asia and Pakistan. North American growers brought it over in the 1700s as a shade tree. It has since gone wild in many parts of the northeastern and upper midwestern United States.

In gardens this maple reaches 40 to 50 feet (12 to 15 metres) tall, with a similar spread. Some trees reach 60 feet (18 metres), and old wild trees may top 80 feet (24 metres). The crown is dense and rounded, and open-grown trees are often wider than tall. Growth is fast when young and moderate later.

The leaves sit in opposite pairs and measure up to 7 inches across. Each has five sharp-pointed lobes and looks much like a sugar maple leaf. Break a leaf stalk and it bleeds milky sap, a handy identification clue. Leaves turn yellow late in autumn, often near the end of October. Young twigs are smooth and reddish brown, with plump buds that shift from green to maroon. The bark is gray-brown to grayish black, with shallow, narrow ridges.

In early spring, before the leaves open, clusters of small yellow-green flowers appear. These corymbs bloom from March to April and attract pollinators. Paired samaras follow, with wings spread almost flat in a straight line. Each samara is about 1.5 to 2 inches long. The fruits ripen in late summer, fade from green to tan, and can hang on into winter.

The tree tolerates sun or part shade but grows best in full sun. It copes with sand, clay, chalk and both acid and alkaline soils if drainage is good. It handles heat, drought and city pollution, and it suits USDA zones 3 to 7. The RHS rates it H7, the hardiest category. Gardeners have long used it as a shade or street tree. Many sources now discourage street planting.

The problems are real. Shallow roots lift sidewalks and drives and compete with lawns. The heavy shade makes it hard to grow anything under the canopy. Verticillium wilt can kill the tree, and young bark may suffer sunscald or frost cracks. Other threats include leaf scorch, honey fungus, gall mites, aphids, caterpillars and horse chestnut scale. The tree seeds heavily, and seedlings crowd out native plants. Several northeastern states list it as invasive.

You can tap the trunk in early spring and drink the sap or boil it into syrup. It holds less sugar than sugar maple sap. Sources report no known hazards. The hard, fine-grained wood makes small household items, and the bark gives a rose-coloured dye.