Western Hemlock vs. Eastern Hemlock Tree: 4 Differences Between These Towering Giants

Hemlock trees are elegant conifers with a conical growth habit and slightly weeping branches. They’re large parts of the landscape across the United States and into Canada. Though the genus Tsuga comprises 14 different species, the ones you might encounter are the western and eastern species of hemlock trees. Below we’ll go through the easiest ways to differentiate between these towering hemlocks and what their main differences are.

Major Differences in Western and Eastern Hemlocks

The main differences you’ll see in these two species of tree are its location and size. There are also smaller differences in its foliage and usage, but those aren’t as obvious at a glance. Fortunately, since they do not share regions, you can most likely figure out which one you’re seeing based on your geographic location. However, even if this was not the case, there are still some readily recognizable differences between the species.

An important disclaimer about misleading common names: the hemlock genus Tsuga is not related to the poison hemlock, or Conium maculatum.

Location

As the common name suggests, western hemlock trees (Tsuga heterophylla) are native to the west coast of North America. They span from central California into the most southern coastal region of Alaska, the Kenai Peninsula. For the most part, this hemlock species prefers more humid climates. They grow well in rocky areas and are highly shade tolerant. Though mostly a coastal species, you can still find western hemlocks in more inland areas like Idaho and Montana.

Eastern hemlocks (Tsuga canadensis) are found in the eastern half of the United States. It also grows well into Canada, including the provinces of New Brunswick and Nova Scotia. Eastern hemlocks meet its western edge in Minnesota and can be found as far south as the Appalachian Mountains in Georgia.

The eastern hemlock species can grow in similar conditions as the western. Both are tolerant of cool, moist weather and high elevations. Acidic soils are key to growing well. Seedlings can take a long time to establish and can take a long time (possibly up to 30 years) to mature and reproduce.

Size

The western hemlock has its eastern cousin beat by far when it comes to height. This species can reach an impressive height of 230 feet, though most are around 100-150 feet tall. Their width is massive, too. The average spread for its canopy is around 30 feet and the trunk diameter can be anywhere from 2-4 feet wide.

Eastern hemlocks are smaller, measuring between 60-70 feet tall. Its canopy spread can be, on average, slightly larger than the western species at 25-35 feet wide. The trunk of the largest specimens can reach 3 feet wide, though generally, the trunk is a slim 1-2 feet in diameter. Since eastern hemlocks are smaller, they’re easier to use in landscaping. They can be put in groups together to form a dense privacy wall, but this slow-growing tree takes its time reaching its maximum height. Think about 200 years into the future if you want an established eastern hemlock privacy wall!

Leaf Appearance

Though both of these species have similar-looking needle-like foliage. Both trees have a two-ranked leaf arrangement, meaning if you were to take a branch and lay it on a table, it would be almost completely flush with the surface. There are two white lines present on the undersides of the needles in both hemlock species and are glossy on top.

The needles range from 1/4 inch to 3/4 inch long in the western hemlock species and are irregular. Eastern hemlocks have needles around 1/2 inch long and are fairly regular in size throughout the tree. On young eastern hemlocks, you can see long hairs are present, whereas the western hemlock, like its needles, has a mix of long and short hairs on the young shoots.

Cones on these species are not very different from each other. Both species have cones around 3/4 of an inch long. If you spot an evergreen with cones longer than 3/4 of an inch, it’s likely not a hemlock.

Characteristics and Use

Western hemlocks grow at a slightly higher altitude, around 6,000 feet in elevation compared to 5,000 for eastern hemlocks. They both have a similar overall shape to them, though western hemlocks have more of a “droop” to them. Aside from noticeable differences in their appearance, they also have different characteristics to the wood and leaves.

Western hemlocks are strong and good for building cabinets, flooring, and windows. It’s an important timber species for the Pacific Northwest and is the second most important timber species. Many different forms of wildlife make use of this tree too, from eating the seeds to the bark or using it as a place to nest.

Eastern hemlocks aren’t as useful commercially, though they do have some value for their pulp which is useful in the paper industry. They are popular for landscaping, as they’re tall and can provide privacy for a large area. Their elegant branches and flat, evergreen needles are attractive and slightly longer than the western species, aiding in a “weeping” look. The eastern hemlock also has a lighter, more cinnamon-colored bark whereas the western hemlock has a dark brown bark color at maturity.

Summary of Differences