How to Grow: Canadian Hemlock

Tsuga canadensis

Other Name

Eastern hemlock

Sun Requirements

full sun, part sun

Bloom Period and Seasonal Color

Grown mostly for its deep green needles and majestic form

Mature Height x Spread

40 to 70 feet x 25 to 35 feet. There are creeping, weeping and shorter forms as well.

Added Benefits

Native

Canadian hemlock is an evergreen, native tree that is often found in New England forests. This beautiful tree can be seen growing along streams and wet areas in the woods providing quiet place for rest and contemplation. But this just isn’t a fine specimen tree.  You’ll be amazed as the different forms of this native tree. Hemlocks can be trimmed into beautiful, large hedges. Also, there are creeping forms that act like ground covers, weeping forms that make interesting additions to gardens, and dwarf forms that mix well in a small tree and shrub border. Unlike many other needled evergreens, hemlock can tolerate shade making them good choices for hedges and shrubs around shady yards.

When, Where and How to Plant

Canadian hemlock is hardy throughout New England. Purchase plants from a local nursery. Plant in spring or summer on well-drained, moist soils. Avoid hot, dry windy locations and areas where there is air pollution and salt spray, such as close to a road. Space plants 30 to 40 feet apart; closer for dwarf forms or if grown in a hedge.

Growing Tips

Keep trees well watered. Mulch annually with pine needles, bark or wood chips to maintain soil moisture conditions, creating a mulch ring to avoid trunk damage due to lawn mowers or string trimmers. Fertilize in spring with an evergreen tree plant food.

Regional Advice and Care

If growing hemlock as a specimen tree, only prune off dead branches. When growing as a hedge plant, trim in spring when the new growth appears. Shear the hedge so the top is narrower than the bottom to prevent bottom branches from dying off due to lack of light. Avoid planting Canadian hemlock in areas with the wooly adelgid insect. This pest is can kill a tree in a few years. Protect young trees from deer browsing with a fence or repellent sprays.

Companion Planting and Design

Canadian hemlocks look very natural planted in a wooded area or near streams. Grow them as hedges to block a view or mark a boundary line. Grow shorter, shrub forms as foundation plants along the shady part of your home near other shade lovers such as rhododendrons. Plant weeping forms as focal points in a mixed shrub border. Plant creeping forms in a rock garden or to cascade over a wall.

Try These

For large trees and hedges, look for the species form of Canadian hemlock. ‘Pendula’ is a popular weeping form that grows 15 feet tall and wide. ‘Horsford Contorted’ is a dwarf, contorted form with twisted branches.  ‘Cole’s Prostate’ is a good creeping form that grows only 1 foot tall. ‘Jeddeloh’ is a shrub form similar to the popular bird’s nest spruce. ‘Aurea Compacta’ is a dwarf shrub with yellow needles.

Excerpted from my book, New England Getting Started Garden Guide.

Go here for a video on how to plant a tree