🔴 Invasive - Remove
Norway Maple
Acer platanoides
This is an invasive species that harms native ecosystems. It should be removed when found to protect local plant and wildlife habitats.
Description
A common street tree that seeds itself into every nearby woodland. Broad five- to seven-lobed leaves, milky sap in the leaf stalk, and a canopy so dense that nothing grows beneath it. Carpets of its seedlings crowd out native maples and oaks.
Where you'll find it
- Planted as a street tree, and then everywhere downwind of one: park edges, back gardens, woodland understory.
- Under its own canopy, where a dense carpet of seedlings comes up and nothing native gets through.
Background
Native to: Europe and western Asia
Introduced in 1756 by the Philadelphia nurseryman John Bartram and planted on streets across the country for two centuries, especially as a replacement for elms lost to Dutch elm disease.
Ecological impact
Its shade is deeper and its leaves fall later than native maples, so the ground beneath it stays bare of wildflowers and tree seedlings — except its own. Shallow roots outcompete neighbours for water.
How to identify
The leaf
Colour and texture: Broad, five-lobed and dark green, very like a sugar maple. The check never fails: snap the leaf stalk off. Norway maple bleeds milky white sap; native maples run clear.
The tell: snap a leaf off at the stalk. Norway maple oozes milky white sap; sugar and red maple sap is clear.
Leaves: opposite, 4–7 inches, wider than long, with 5–7 lobes ending in fine points; stay green into November.
Bark: grey with regular, shallow, interlacing ridges — neater than sugar maple’s shaggy plates.
Buds: rounded and reddish-green; sugar maple’s are brown and sharply pointed.
Seeds: paired samaras spread almost flat, nearly 180 degrees apart; sugar maple’s hang in a U.
Seedheads & fruit
Seeds September–October.
Paired winged keys spread almost straight out from each other in a wide, flat line, close to 180 degrees.
Why it matters: Native sugar maple keys hang in a narrow horseshoe instead. The spread of the wings tells you which tree is seeding the seedling carpet you are about to pull.
Preferred removal method
Wrench the crown out
A woody crown too big to pull and too stubborn to cut: wineberry, multiflora rose, barberry, bush honeysuckle, tree seedlings.
- 1Cut the top growth back first so you can reach the base, then clamp the weed wrench jaws as low as you can, at soil level.
- 2Lever the handle back in one long, steady arc. Let the tool do it, not your back.
- 3The root ball should lift with the stem. Shake the soil off, and leave the hole; stamping it closed buries any seed you just exposed.
Avoid: Do not clamp halfway up the stem. It snaps, and the crown stays in the ground and re-sprouts.
Grab from the kit, in this order
Disposal
It can stay on site. Pulled seedlings and wrenched saplings can stay on site. Bag the winged seeds if the sapling you pulled is carrying any.
Don't confuse with a lookalike
Native Sugar Maple vs Norway Maple
Norway maple was planted as a street tree everywhere, and its seedlings now carpet the ground under it where nothing native gets through. The trouble is that it looks like a sugar maple, and pulling a sugar maple seedling is a real loss. One check never fails and takes two seconds: snap a leaf stalk off and look at the cut.
Sugar Maple
Acer saccharum
Native: keepSmooth U-shaped notches between the lobes.
