Eastern Hemlock
Tsuga canadensis
Overview
Majestic native evergreen found throughout Eastern Ontario's forests. Provides critical winter cover for wildlife and creates cool, shaded understory habitats.
Bark was historically used for leather tanning. Old-growth hemlocks can live 800+ years and are among Ontario's longest-lived trees.
Identification
Leaves
Short, flat needles with rounded tips attached by tiny stalks. Dark green above with two distinctive white stripes below. Needles arranged in flat sprays.
Bark
Bark becomes thick and deeply furrowed with age, forming broad, flat-topped ridges. Rich in tannins historically used for leather tanning.
Flowers
Male cones are small yellow structures. Female cones develop at branch tips.
Fruit
Small oval cones (0.5-1 inch) hang from branch tips. Important food source for red squirrels, chickadees, and other wildlife.
🦆 Valuable wildlife food source
Growing Conditions
Climate
Native to the cool, moist ravines and north-facing slopes of Eastern Ontario. Sensitive to hot, dry, exposed conditions.
Hardiness Zones: 3, 4a, 4b, 5a, 5b
Light Requirements
Soil
Moisture: moist
Drainage: well-drained
pH Range: 5 - 6.5
Tolerance
Care & Maintenance
Pruning
Best Season: Spring
Frequency: Rarely needed
- Best left unpruned for natural form
- Can be sheared for hedges in spring
- Remove dead branches as needed
Avoid: Fall - allows disease entry before winter
Watering
Establishment: Consistent moisture essential for first 3 years
Mature: Supplement during dry periods
Seasonal Care Timeline
Spring
- Inspect for Hemlock Woolly Adelgid
- Check for winter damage
- New growth emerges
Summer
- Drought stress monitoring critical
- Spider mites in hot, dry conditions
Fall
- Second inspection window for HWA
- Prepare for winter with adequate moisture
Winter
- Evergreen provides wildlife shelter
- Heavy snow can cause branch breakage
- Desiccation from winter winds
Common Issues
Hemlock Woolly Adelgid
SevereInvasive aphid-like insect threatening hemlocks across eastern North America
Symptoms: White cottony masses at needle bases, Needle yellowing and drop, Branch dieback, Thin crown
Treatment: Systemic insecticides, horticultural oil applications
Prevention: Early detection through regular monitoring, avoid moving infested material
Professional arborist recommended
Elongate Hemlock Scale
ModerateScale insect causing needle yellowing
Symptoms: Yellow needles, White waxy scale on needle undersides
Treatment: Horticultural oil, systemic insecticides
Prevention: Maintain tree vigor
Professional arborist recommended
Quick Facts
When to Call an Arborist
Recommended inspection: Annual inspection critical due to HWA threat
- •White cottony masses on branches (HWA)
- •Significant needle loss
- •Crown thinning
- •Branch dieback
Free consultation for Belleville residents
Recommended Services
Based on Eastern Hemlock characteristics