Sugar Maple
Acer saccharum
Active Threats to Sugar Maple
LDD Moth (Spongy Moth)
Formerly known as Gypsy Moth. Caterpillars defoliate trees in late spring, with periodic outbreak years causing severe damage.
Signs to watch for:
- •Visible caterpillars with blue and red spots
- •Skeletonized or completely eaten leaves
- •Egg masses on tree trunks (tan, fuzzy patches)
- •Frass (caterpillar droppings) under trees
Recommended Action: Healthy trees typically survive defoliation. Repeated years of heavy feeding may require professional intervention.
Free consultation available
Maple Tar Spot
Common fungal disease causing black spots on maple leaves. Mostly cosmetic and does not seriously harm healthy trees.
Signs to watch for:
- •Black tar-like spots on leaves
- •Yellow halos around spots
- •Early leaf drop in severe cases
Recommended Action: Rake and dispose of fallen leaves in autumn to reduce spores. No treatment typically needed.
Free consultation available
Overview
Iconic tree of Eastern Ontario, source of maple syrup production, featured on Canadian flag
Sugar maples have been tapped for syrup by Indigenous peoples for centuries and remain economically important to the region
Identification
Leaves
Distinctive 5-lobed leaves with smooth margins, turning brilliant orange-red in fall. The Canadian flag maple leaf is modeled after this species.
Bark
Young trees have smooth gray bark that becomes deeply furrowed with age, developing long vertical plates that sometimes curl outward.
Flowers
Small yellow-green flowers appear in early spring before leaves emerge, hanging in drooping clusters.
Fruit
Paired winged seeds (samaras) that hang in clusters and spin as they fall, maturing in autumn.
🦆 Valuable wildlife food source
Growing Conditions
Climate
Well-adapted to Eastern Ontario climate with excellent cold hardiness and tolerance for temperature extremes
Hardiness Zones: 3, 4a, 4b, 5a, 5b
Light Requirements
Soil
Moisture: moist
Drainage: well-drained, moderate
pH Range: 5.5 - 7.3
Tolerance
Care & Maintenance
Pruning
Best Season: October-November, December-February
Frequency: As needed for structure when young
- Prune in October-November or December-February to minimize sap bleeding
- Professional arborists can prune in late winter (February-March) with proper techniques to minimize sap loss
- Remove crossing or rubbing branches
- Maintain central leader when young
Avoid: April-May when sap flow is heaviest
Watering
Establishment: Weekly deep watering for first two years
Mature: Supplemental during drought only
Seasonal Care Timeline
Spring
- Maple syrup tapping season (February-March)
- Potential for late frost damage to new growth
- Watch for aphid activity
Summer
- Watch for drought stress in young trees
- Monitor for tar spot development
- Check for leaf scorch during heat waves
Fall
- Heavy leaf drop requires raking
- Clean up fallen leaves to reduce disease pressure
- Brilliant fall color display attracts attention
Winter
- Ice damage possible on weak branches
- Sunscald on young trunks
- Snow load on branches
Common Issues
Tar Spot
LowBlack spots on leaves caused by fungal infection
Symptoms: Black tar-like spots on leaves, Yellow halos around spots
Treatment: Rake and destroy infected leaves in fall
Prevention: Good air circulation, remove fallen leaves
Verticillium Wilt
SevereFungal disease affecting vascular system
Symptoms: Wilting leaves, Branch dieback, Discolored streaks in wood
Treatment: Remove affected branches, improve tree vigor
Prevention: Avoid planting in infected soil, maintain tree health
Professional arborist recommended
Maple Shoot Borer
ModerateBeetle larvae that tunnel into shoots
Symptoms: Wilted shoot tips, Small holes in stems, Dead shoots
Treatment: Prune and destroy affected shoots
Prevention: Keep tree healthy, monitor in early spring
Quick Facts
When to Call an Arborist
Recommended inspection: Annual inspection recommended
- •Sudden wilting or dieback of large branches
- •Significant lean or structural defects
- •Large cracks or splits in trunk
- •Fungal growth on trunk or roots
- •Extensive pest infestation
Free consultation for Belleville residents
Recommended Services
Based on Sugar Maple characteristics