Canadian Hemlocks

I couldn’t resist this stately conifer of the East, and have five in my garden. One of a very small group of conifers that tolerate shade, it’s also threatened by a virulent Asian insect that I’m happy to report can be dealt with successfully by the watchful gardener.

Here’s an article I wrote about the destruction of hemlocks in the wild caused by the woolly adelgid insect (lower photo). It includes two remedies for protecting hemlocks, both do-able by the home gardener.

The Canadian Hemlock (Tsuga canadensis) is native from Georgia to New Brunswick and west to Wisconsin.

Details

• In the wild they grow to 40-70 feet tall. In urban situations they often stop growing at 25 feet tall by 10 feet wide.
• Abundant dwarf forms are available, the most popular of which is the weeping variety ‘Pendula’ (bottom photo).
• Tolerates full sun to full shade, though it does best in partial sun/shade.
• Hardy to Zone 3.
• Sources say that deer eat hemlocks, but mine haven’t suffered even a nibble in my deer-infested backyard.

Care

• Average drought tolerance after first year or so on site.
• Avoid roadsides (salt spray) and exposed sites (unbroken wind).
• Stake new hemlocks for 2-3 years.
• Can be sheared to form a hedge, according to all the sources, but that would sure spoil its gorgeous shape and form.
• Sources warn to be careful if transplanting in the fall and recommend watering well and mulching, but you’d do that anyway, right?

by Susan Harris

Photo credits: Top, University of Vermont. Bottom, by Brooklyn Botanic Garden.