Tsuga canadensis (Canada Hemlock)

Michael's Opinion

The Canada Hemlock is a graceful tree suitable for large areas. It would really do justice to put the Hemlock near a pond where it can hang over the water giving it a whimsical appearance. Looks best when left in its natural state; not pruned.

Botanical Information

FamilyPinaceae
GenusTsuga
Speciescanadensis
CategoryWoody
TypeTree (evergreen)
OriginIntroduced into cultivation in 1736. The only hemlock native to Eastern Canada. Occurs in eastern North America, from Ontario and Nova Scotia to Indiana and Kentucky.
Pronunciation

Details

USDA Hardiness Zone 4-7
USDA Hardiness Ref.
Canadian Hardiness Zone4b
Canada Hardiness Ref.
RHS Hardiness ZoneH7
RHS Hardiness Ref.
Temperature (°C)-40
Temperature (°F)-40
Height13 -30 m
Spread8 m
GrowthSlow
Flowering PeriodApril

Description and Growing Information

General DescriptionIt is from the cold north-eastern climate of North America and is a medium sized tree that extends up to 24 m, with a trunk that is usually tapered at its base. Forms a broadly pyramidal crown; its hanging branches have pensile tips.
ID CharacteristicYou can determine the Eastern Hemlock from all other native eastern conifers by its slender twigs and oblique leading shoot. It has ‘nodding’ branch ends; the top of its crown has a slender 'leader' that cascades downwards.
ShapeUpright, weeping, conical, pyramidal habit. Tapered trunk in youth, pendulously pyramidal with age.
LandscapeCan make a remarkably handsome evergreen hedge. There is a very good example of this in the Arboretum at the Royal Botanical Gardens in Burlington. Also suited to screening, groupings, as an accent plant, or used in a park or institutional setting.
PropagationPropagate from seed in the spring. Stratify seeds for 1-4 months at about 1-5°C to ensure good germination. Semi-ripe cuttings harvested from January to mid-February and placed on a bench with a bottom heat of 18°C.
CultivationRoot pruning aids transplanting. Moist, well-drained, acidic soils; soil pH of 5.0-6.5 is preferable; transplant in early spring. Tolerates shade, can grow in full sun with well-drained soil. Prune individual shoots, instead of shearing the entire plant.
PestsWoolly adelgid has been the biggest insect menace to the Hemlock thus far. Other threats to the Hemlock are: rust, mite, hemlock looper, spruce leaf miner, gypsy moth, hemlock sawfly hemlock fiorinia scale and sunscorch.
Notable SpecimensThere is a fine specimen of Tsuga canadensis ‘Calvert’ situated in a courtyard at the Royal Botanical Gardens in Burlington, Ontario, Canada. Rayner Gardens, London, Ontario, Canada has some excellent climax specimens along the park edge bordering the Thames River.
HabitatRocky ridges, ravines, hillsides. Extends through southern limits of Northern Ontario.
Bark/Stem DescriptionScaly in youth, becoming deeply grooved with dark brown, broad, flat-topped ridges. Outer bark is dull reddish purple, inner bark is bright reddish purple. The bark contains tannin, which at one time was a commercial source for tanning leather.
Flower/Leaf Bud DescriptionMinute, ovoid shape with fuzzy scales, light brown in colour, 2 mm in size.
Leaf DescriptionSmall ovoid needles, arranged in 2 rows; greyish brown and pubescent when young, maturing to glossy dark green, 2 greyish bands on undersides, notched with a short leaf stalk. Leaves are 0.5-1.7 cm long, and 20-30 mm wide.
Flower DescriptionMonoecious; light yellow stamens, pistil is pale green. Male flowers are auxiliary on previous year’s shoots. Female flowers are green coloured and are terminal on last year’s lateral shoots: they also have imbricated scales.
Fruit DescriptionPendulous cones are stalked, slender and ovoid, apex is almost obtuse. Cones are 1-2.5 cm long, and 0.05-1 cm wide. Brown in colour when mature and arising from branch ends hanging downwards. Cones shed their seeds during the autumn.
Colour DescriptionRetains its green colour throughout the seasons.
Texture DescriptionSoft and fine textured.

Photographs