Green Ash
Fraxinus pennsylvanica
Active Threats to Green Ash
Emerald Ash Borer
Invasive beetle devastating ash trees across Eastern Ontario. All ash species are at risk.
Signs to watch for:
- •D-shaped exit holes in bark
- •Canopy dieback starting from top
- •Bark splitting and woodpecker damage
- •S-shaped larval galleries under bark
Recommended Action: All ash trees should be assessed by a certified arborist to determine treatment options or removal timeline.
Free consultation available
Overview
Once common street and landscape tree, now critically threatened by Emerald Ash Borer
Widely planted as replacement for elms, now itself facing widespread mortality from EAB
Identification
Leaves
Compound leaves with 5-9 lance-shaped leaflets arranged oppositely along the stem. Leaflets are serrated and turn yellow in fall.
Bark
Develops distinctive interlacing diamond pattern of ridges with age.
Flowers
Inconspicuous purple to greenish flowers appear before leaves in spring.
Fruit
Single-winged seeds (samaras) hang in clusters, persisting into winter.
🦆 Valuable wildlife food source
Growing Conditions
Climate
Well-adapted to Eastern Ontario climate and variable conditions, but EAB has changed outlook
Hardiness Zones: 3, 4a, 4b, 5a, 5b
Light Requirements
Soil
Moisture: moist, wet
Drainage: well-drained, moderate, poor
pH Range: 5 - 8
Tolerance
Care & Maintenance
Pruning
Best Season: October-March
Frequency: Minimal when mature
- Prune in October-March during dormant season
- Establish strong structure when young
- Remove dead or damaged branches
Avoid: Spring and summer to reduce stress
Watering
Establishment: Regular watering for first 2 years
Mature: Tolerates both wet and dry conditions
Seasonal Care Timeline
Spring
- Monitor for Emerald Ash Borer emergence (May-June)
- Timing for insecticide treatments if protecting tree
- Early detection is critical
Summer
- Peak EAB activity period
- Monitor for decline symptoms
- Consider treatment options for valuable specimens
Fall
- Assess tree health
- Plan for removal if heavily infested
- Consider replacement species
Winter
- Look for woodpecker damage indicating EAB
- Plan management strategy for spring
Common Issues
Emerald Ash Borer
SevereHighly destructive invasive beetle that kills ash trees
Symptoms: D-shaped exit holes, Bark splitting, Crown dieback, Woodpecker activity
Treatment: Systemic insecticide treatments for high-value trees, otherwise removal
Prevention: Preventative insecticide treatments, early detection monitoring
Professional arborist recommended
Ash Yellows
HighPhytoplasma disease causing decline
Symptoms: Yellowing foliage, Stunted growth, Tufted branches, Premature fall color
Treatment: No cure, remove severely affected trees
Prevention: Plant resistant species
Professional arborist recommended
Quick Facts
When to Call an Arborist
Recommended inspection: Annual inspection critical for EAB detection
- •Any signs of Emerald Ash Borer
- •Crown thinning or dieback
- •D-shaped exit holes in bark
- •Increased woodpecker activity
- •Bark splitting or unusual sprouting
Free consultation for Belleville residents
Recommended Services
Based on Green Ash characteristics