Troubleshooting
Norway Maple problems — and how to fix them
Norway Maple (Acer platanoides) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Tar spot (Rhytisma acerinum)
Black blotches on foliage in late summer; purely cosmetic; rake up and bin infected leaves to reduce next year's infection.
Aphids (Norway maple aphid)
Heavy infestations cause leaf curl and honeydew drip below the canopy; rarely seriously harmful on mature trees.
Sooty mould
Black coating on surfaces beneath the canopy, following aphid honeydew; treat the aphid infestation to resolve.
Verticillium wilt
Sudden die-back of branches; no cure — prune out affected limbs and sterilise tools. Avoid planting in known infected soil.
Invasive seedlings
Norway maple self-seeds prolifically; in some regions it is considered invasive. Remove seedlings promptly and consider sterile cultivars.
Prevent norway maple problems before they start
Most norway maple issues are care-mismatch, not bad luck. Dial in the basics:
Norway Maple problems — FAQ
Why is my norway maple tar spot (rhytisma acerinum)?
Black blotches on foliage in late summer; purely cosmetic; rake up and bin infected leaves to reduce next year's infection.
Why is my norway maple aphids (norway maple aphid)?
Heavy infestations cause leaf curl and honeydew drip below the canopy; rarely seriously harmful on mature trees.
Why is my norway maple sooty mould?
Black coating on surfaces beneath the canopy, following aphid honeydew; treat the aphid infestation to resolve.
Why is my norway maple verticillium wilt?
Sudden die-back of branches; no cure — prune out affected limbs and sterilise tools. Avoid planting in known infected soil.
Why is my norway maple invasive seedlings?
Norway maple self-seeds prolifically; in some regions it is considered invasive. Remove seedlings promptly and consider sterile cultivars.