Like all plants, western hemlock trees have to have a way of continuing their species. But, being an evergreen and a conifer, these magnificent trees have a slightly different method of doing so than many of the plants you’re more familiar with. So, how does the western hemlock reproduce? What is the growth rate of the young trees? Keep reading as we explore the answers to these questions and more!
What You'll Learn Today
How Does Western Hemlock Reproduce?
Western hemlock is a conifer (like many others), which means that it produces pine cones instead of flowers. These pine cones are the seed-bearing structures of the trees.
Western hemlocks produce both male and female pine cones on a single tree. The male pine cones produce bits of pollen that are released at maturity; these bits of pollen blow in the wind to reach the female pine cones.
Meanwhile, female pine cones are slightly larger than the male pine cones, and they contain many infertile seeds. When they receive the pollen bits from the male flowers, the seeds are fertilized and begin to develop inside the cones.
Western hemlock pollination season takes place in the spring, from April in the southern parts of its range through June in the northern areas. The seeds inside the female cones develop throughout the summer months, reaching maturity by September and falling from the cones in October.
About half of the seeds in a mature pine cone are viable. When the pine cone opens to release the seeds, they blow on the wind and may be carried more than a mile away from the parent tree.
Western hemlock pine cones are small, no more than an inch or two long. Each tree produces many new pine cones each season, and old pine cones may remain on the trees for a couple of years after releasing their seeds.
Can Western Hemlock Be Propagated?
Propagation is a method of producing new plants without the use of seeds. Western hemlock trees can be successfully propagated using the following methods:
Layering
Layering involves rooting a branch of a plant before removing it from the parent plant. Many plants layer naturally, such as tomatoes and strawberries.
Western hemlock can be layered by burying a section of a low-hanging stem under soil, or by mounding soil up around the stem above one or more branches that have shot off from the main stem.
This is typically done in the spring, and by the fall the buried sections should have sprouted roots; these are dug up and severed from the main plant.
Cutting
Cutting is a simpler process than layering; all you have to do is remove branches from the parent plant and place them in water or soil to develop roots. That said, not all cuttings root successfully.
Western hemlock can be propagated in this way, but it is almost easier to grow a new plant from seed. If you decide to propagate a western hemlock by cutting, it might help to add a rooting agent to the water or soil to encourage it to grow roots.
Similarly, cuttings from western hemlock can be easily grafted into existing trees. As long as the graft is performed correctly, the new stem is highly likely to take; there are few issues with compatibility between the scion (cutting) and rootstock (the existing plant).
According to the USDA, grafts are more likely to be successful than rooted cuttings.
What is the Growth Rate of a Western Hemlock?
Western hemlock seedlings grow very slowly at first, and they may be damaged or killed by extreme heat, cold, fire, and poor soil quality. They need loose, loamy soil full of organic material, and they do best when they sprout in shady spots.
Seedlings that survive their first year continue to grow very slowly. It is common for two-year-old hemlocks to stand no more than eight inches tall.
It takes time for these trees to establish themselves, but once they do, they begin growing more rapidly. Trees that are several years old and in optimum growing conditions may add as much as 24 inches to their height every year.
Western hemlocks may begin producing pine cones anytime after the age of ten, though in most cases they don’t begin successfully reproducing until they are 25 to 30 years old.
They typically live for around 300 to 500 years, though some western hemlocks have been known to live more than 1,200 years.
Check out this video to learn more about western hemlock trees:
Conclusion
Western hemlocks reproduce via seeds in their female pine cones which are fertilized by bits of pollen from the male pine cones. They can also be propagated to create rooted seedlings from branches, and fresh cuttings can easily be grafted into other trees.
