When to Plant a Hemlock Tree?

The western hemlock grows to 100 feet in height.

Hemlock is a species of evergreen trees of the genus Tsuga. Western, eastern and Canadian hemlock are all North American natives and important lumber trees. The term "Tsuga" is a meld of the Japanese words for "tree" and "mother." Although these tall evergreens smell like the poison hemlock plant -- renowned as the source of the poison that killed Socrates -- they are not related.

Identification

Eastern hemlock (Tsuga canadensis) is a tall, slow-growing evergreen that can live up to 800 years. This giant -- rising 175 feet in favorable locations -- grows well in cool, humid climates. Western hemlock (Tsuga heterophylla) grows near the coast, earning its nickname "Pacific" hemlock. It also often exceeds 100 feet in height, with a straight trunk and slightly down-sloping branches. All hemlocks are evergreen, which means that gardeners cannot look to leaf-fall to signal planting time.

Preparing for Planting

Hemlock trees are conifers, which have a reputation of being hard to transplant.You can avoid myriad difficulties by preparing an appropriate planting site well in advance of the early fall planting time. Select a site with well-drained, fertile earth that gets regular sun. Nurseries offer hemlocks in containers or root balls with plenty of soil around the roots, so dig the planting hole large enough to accommodate the entire root presentation.

Planting Time

The fall planting dates for deciduous trees, running into November, are too late for evergreens such as hemlock. Since hemlocks do not go dormant, no advantage exists for late planting. Instead, plant hemlocks when the heat of summer has passed but the soil temperature remains elevated to 60 to 70 degrees Fahrenheit. In most locations, this means mid-August through September. Your hemlock will have time to establish its roots before the first winter freeze arrives.

Alternative Planting Dates

For those who miss the fall deadline, plant your hemlock in spring. As in the fall, push the planting date for hemlock closer to warm weather than for deciduous trees. Many gardeners favor spring planting because the season is inevitably followed by milder weather, whereas winter sometimes arrives sooner and harsher than expected. Whichever season you select, be sure to water your young hemlock regularly during the first year after planting.

References

• U.S. Forest Service; Tsuga Canadensis (L.) Carr. Eastern Hemlock; R. M. Godman, et al.
• Boreal Forest; Tsuga Heterophylla
• Iowa State University Extension; Fall Planting of Trees and Shrubs; Jeff Iles; August 22, 1997