Introduction
Weeping Canadian hemlock may be one of the most beautiful conifers, with its soft green needles attached to gently weeping branches reaching to the ground. Specimen trees look their best with lower branches left on and touching the ground. The strong, conical form typical of the species is completely lost in this cultivar. The tree is usually trained to grow several feet tall then allowed to spread up to two times its height. In 80 years the tree may be 12 feet tall and 25 feet wide. It makes one of the most impressive accents or specimens of any tree available in this country. Unfortunately, infestations of woolly adelgid have been severe in Virginia, Maryland, and Pennsylvania (and other areas) and this may limit their use in these regions.
General Information
Scientific name: Tsuga canadensis
Pronunciation: TSOO-guh kan-uh-DEN-sis
Common name(s): Weeping Canadian hemlock, weeping eastern hemlock
Family: Pinaceae
USDA hardiness zones: 4A through 7A (Fig. 2)
Origin: native to North America
Invasive potential: little invasive potential
Uses: specimen; container or planter
Availability: not native to North America
Description
Height: 10 to 12 feet
Spread: 20 to 30 feet
Crown uniformity: irregular
Crown shape: weeping
Crown density: dense
Growth rate: slow
Texture: fine
Foliage
Leaf arrangement: alternate (Fig. 3)
Leaf type: simple
Leaf margin: entire
Leaf shape: linear
Leaf venation: parallel
Leaf type and persistence: evergreen, needled evergreen, fragrant
Leaf blade length: less than 2 inches
Leaf color: green
Fall color: no color change
Fall characteristic: not showy
Flower
Flower color: yellow, green
Flower characteristics: not showy
Fruit
Fruit shape: oval, cone
Fruit length: .5 to 1 inch
Fruit covering: dry or hard
Fruit color: brown
Fruit characteristics: does not attract wildlife; not showy; fruit/leaves not a litter problem
Trunk and Branches
Trunk/bark/branches: branches droop; not showy; typically multi-trunked; thorns
Pruning requirement: needed for strong structure
Breakage: resistant
Current year twig color: gray, brown
Current year twig thickness: thin
Wood specific gravity: 0.40
Culture
Light requirement: full sun, partial sun, partial shade, shade tolerant
Soil tolerances: sand; loam; acidic; well-drained
Drought tolerance: moderate
Aerosol salt tolerance: low
Other
Roots: not a problem
Winter interest: yes
Outstanding tree: yes
Ozone sensitivity: unknown
Verticillium wilt susceptibility: resistant
Pest resistance: sensitive to pests/diseases
Use and Management
Hemlock transplants well balled-in-burlap and will grow in moderately dry or moist, acidic soil but prefers moist, well-drained sites. Root rot and bark splitting are common on sites which are constantly wet. Some die-back can be expected after transplanting if irrigation is not managed just right. Best growth is in partial shade in the mountainous valleys but specimens grow well in full sun in the middle and northern part of their range. Perfect when partially shaded from other trees where soil is cool and some sun sneaks through during portions of the day. It is not for planting in a lawn in competition with turf unless turf is eliminated beneath the canopy. Plants grown in full shade will be thin and will not produce the specimen effect so characteristic of weeping hemlock in full sun or partial shade. This is a picky plant but well worth the extra effort to cultivate it.
Other cultivars include: 'Bennett'—globose habit, branches weeping at the tips, dark green, grow in partial shade, three-foot height and spread; 'White Gentsch'—a rounded, flattened dwarf, the foliage is white at the tips, four feet high and wide.
Pests
Woolly adelgid, scales, weevils, bagworm, mites, sapsucker woodpecker can infest hemlock. Woolly adelgid and scale infestations can devastate a planting.
Diseases
Needle rust, cankers, and non-parasitic bark splitting on heavy, poorly drained soil can cause some problems.
