Eastern hemlock

Sun

Partial shade is ideal; tolerates deep shade. Full sun is suitable in cool climates if the roots remain consistently moist.

Water

Needs evenly moist soil, especially while establishing; poorly suited to drought, hot dry winds or waterlogged ground.

Soil

Cool, humus-rich, well-drained soil, preferably acidic to slightly acidic. Avoid shallow, dry or strongly alkaline ground.

Height

40-70 ft (12-21 m), sometimes taller with age

Spread

25-35 ft (7.6-10.7 m)

Foliage

Evergreen. Short, flat, dark green needles with two pale bands beneath, arranged mostly in flattened sprays. Fine branch tips nod gently; small brown cones hang beneath the branches.

Growth

Slow to moderate; growth slows markedly in deep shade or dry soil.

Care needed

Medium

• Cold hardy
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   8 ft (2.6 m)

3. After 2 years

   10 ft (3.1 m)

4. After 3 years

   12 ft (3.7 m)

5. After 5 years

   16 ft (4.8 m)

About 26 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US and Canada

Growth rate

Slow

• Water deeply during dry spells, keeping the root zone moist but not saturated.
• Spread 2-3 in (5-8 cm) of organic mulch over the root zone, leaving the trunk clear.
• Protect young trees from drying winds and intense afternoon sun in warmer locations.
• Keep digging, paving and heavy foot traffic away from the shallow roots.
• Feed only if a soil test indicates a deficiency; avoid routine high-nitrogen feeding.
• In affected regions, inspect needle bases and twig undersides regularly for white, woolly adelgid deposits.

Pruning. Prune in late winter or early spring to remove dead, damaged or crossing branches. For hedges, lightly trim new growth in late spring or early summer, keeping the base wider than the top and avoiding severe cuts into bare old wood.

Late winter

Remove damaged branches and check twig undersides for hemlock woolly adelgid where it occurs.

Spring

Plant while the soil is workable and moist, setting the root flare at ground level.

Late spring

Refresh mulch and lightly trim hedges after the first flush of growth.

Summer

Water during dry periods and check for yellowing needles, premature shedding or pest activity.

Autumn

Water thoroughly if conditions are dry before the ground freezes.

• Use as a woodland canopy tree above ferns, foamflowers and other shade-tolerant ground plants.
• Plant as a clipped hedge or evergreen screen where there is room for a broad base.
• Place against deciduous trees to provide dark green contrast and winter structure.
• Use as a specimen in a large, sheltered lawn or woodland-edge garden, allowing the lower branches to remain.

Garden styles it suits: Woodland, Traditional, Grand estate, New England, Winter interest and Green on green.

Plant it with: Christmas fern, Foamflower, Wild ginger, Rhododendron, Mountain laurel and Solomon's seal.

Wildlife: Dense branches provide shelter and nesting cover for birds, and the small seeds feed birds and small mammals. Deer may browse young trees, particularly in winter.

• Hemlock woolly adelgid: white woolly deposits at needle bases, thinning foliage and branch dieback can lead to death. In affected parts of eastern North America, seek local extension or arborist advice promptly; treatment choice and timing depend on tree size and local regulations.
• Elongate hemlock scale: small pale or brown scale covers beneath needles cause yellowing and decline. Have the pest identified and use a locally approved, correctly timed treatment.
• Drought and heat stress: browning, needle drop and branch dieback develop on hot, dry sites. Water deeply, maintain mulch and avoid planting where summer drought is routine.
• Root rot: persistently saturated soil can cause decline and root death. Improve drainage before planting; do not try to compensate for poor drainage with extra watering.

Not known to be toxic to cats, dogs, horses or people; the needles, bark and cones are not recognized as poisonous. It is unrelated to highly poisonous poison hemlock and water hemlock. Do not eat unidentified plants.

• Western hemlock (Tsuga heterophylla)

  Western hemlock usually has a more strongly drooping leader and needles of conspicuously mixed lengths within each spray; eastern hemlock needles are more uniform in length.

• Canada yew (Taxus canadensis)

  Canada yew is usually a low, spreading shrub with longer needles and red, fleshy seed coverings rather than hanging woody cones. Unlike eastern hemlock, yew foliage and seeds are highly poisonous.

Tsuga comes from a Japanese name for hemlock, and canadensis means 'of Canada', referring to part of the tree's native range.

Propagation. Usually grown from seed collected from mature cones and given a period of cold, moist stratification before sowing. Named garden forms are generally propagated by specialist cuttings or grafting to preserve their characteristics.

Accepted botanical name

Tsuga canadensis

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alabama, Connecticut, Georgia, Indiana, Kentucky, Maine, Maryland, Masachusettes, Michigan, Minnesota, New Brunswick and New Hampshire.

Measured

Soil pH 4.2 to 5.7. Average height 1460 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.