Collecting Mountain Hemlock for Bonsai

by Graham J. Hues. Page 2 of 2

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mountain hemlock

mountain hemlock

mountain hemlock

mountain hemlock

Before I move into the section on aftercare, I’d like to review just a few thoughts on my limited (seriously started in 2005) bonsai journey.

The more I’ve ventured into the joy of bonsai, when I’m in the “field”, I’ve come to appreciate the natural ecosystems and individual ancient trees/specimens even more than I have before. Now I view them through my “Bonsai Lens”, looking at them to see what characteristics they have that I can incorporate into my own trees. Don’t get me wrong, I’ve always had admiration when I’ve viewed some incredible forests and stands of ancient giants, appreciating them in all their glory; however that was through my “forestry” lens.

Also my bonsai endeavours have been filtered through and influenced by 38 years of working in the coastal rain forests of BC where I’ve had to incorporate the ecology, silvics (and a range of other forest sciences) into making forest management decisions. I also believe that these latter disciplines have helped me greatly in developing healthy trees, creative designs but it has also posed some internal resistance to the classic rules especially when it comes to bonsai soil components, design techniques and foliage pad development) which I cover below.

For me collecting and transforming these sub alpine species into Bonsai is not so much about following the classic rules of bonsai but more about using some basic design factors/principles (rules) and then exposing and capturing Mother Nature’s basic design. The trees that are collected have been shaped through decades of extreme environmental forces/factors which has formed them into unique shapes and forms.

Many of them are surviving, living in and on the outer limits (often extremes) of their optimum growing sites showing their unique adaptability. However, in living (surviving not thriving) on such extremes I find that many are close to dying (or in poor health) but with sound collecting methods and aftercare techniques they can be encouraged to thrive- if you follow the classic mantra “time and patience grasshopper”!

Sub-Alpine Tree Collection and Aftercare

I cannot take credit for much of the following on the aftercare of these types of trees, and thus must give credit here to my mentor who has worked with this species for decades. He has given me his advice, experience and knowledge that I’ve taken and adapted to their collection, aftercare, when and how to repot, what general soil mixtures work, some design principles, and styling/adaption techniques.

His name is Anton Nijhuis (if interested see – his blog has some great photo essay’s of his collecting trips and a pictorial of aftercare treatment). He also has some of the best collected trees in the Pacific Northwest and folks from all over coastal B.C., Washington, Oregon and northern California have visited his garden and bought his trees. In 2010 one of his large collected Hemlock won best in show – Pacific Northwest Bonsai Clubs Associations – Conference/show/AGM.


The one key factor in collection is that generally the root ball is restricted to the upper layers of forest floor (also called duff or humus) which has grown on top of rock and in some cases there might even be a narrow larger of soil between the rock/humus layer. For transportation of the collected tree, we use shrink-wrap or plastic garbage bags which binds the entire root ball.

Once home, they are put into a grow bed or recovery bed where we lay down a 2” layer of fish mulch (see for more information about its properties), the key focus at this time is to ensure that there is firm contact between the root ball and fish mulch layer (no air pockets). More mulch is then added to the sides of the root ball and then 2-3” more goes on top of it.

mountain hemlock

It then is left this way for 2 years (two growing seasons) at which time the tree is placed into a grow pot (plastic 2-5 gallon pot) or training container. My general practice is that I remove some of the original humus/forest floor that breaks apart easily and remove the mountain heather, moss and other plants that came with the original root ball. I take great care not to overly disturb the roots and gentle place the modified tree/root ball (which still contains much of the original forest floor) into a mixture of shifted fish mulch, pumice, some Perlite and lava if available.

I believe that introducing some of the original forest floor into the soil mix is integral for these sub alpine species due to the role of Mycorrhizae, which has been found to be important sinks for carbon and a key components of nutrient cycling. I also believe that to remain healthy the ph has to be on the acidic side (see about the tree below) and this additional original organic material aids in this.

One negative of Mt. Hemlock is that they don’t back bud, so getting the growth back to the mainline/trunk of the tree is difficult however existing foliage can be encourage to grow into some great foliage pads.

A positive note on them is that they are shade tolerant and thus on many specimens they have older dominant/ co-dominant larger branches, which usually have the growth towards the end of the branches. However one key factor in design is that they also have intermediate and suppressed branches which are much younger and closer to the trunk.

One technique that is used if the objective is for a more classic “old growth” look/feel is the removal (over time) of these larger branches in lieu of the smaller ones. These smaller internal branches develop well with the increased light conditions/available nutrients and the larger unwanted branches can be Jin’d to add to the total image.

About the Tree:

Tsuga mertensiana, known as mountain hemlock, is a species of hemlock native to the west coast of North America, with its north-western limit on the Kenai PeninsulaAlaska, and its south-eastern limit in northern Tulare CountyCalifornia.

It is usually found on cold, snowy subalpine sites where it grows slowly, sometimes attaining more than 800 years in age. Arborescent individuals that have narrowly conical crowns until old age (300 to 400 years) and shrubby krummholz on cold, windy sites near timberline add beauty to mountain landscapes

A parkland subzone of single trees and small tree clumps (average canopy cover less than 25 percent), stands dominated by mountain hemlock typically have very acidic forest floors (pH 3.4 to 5.0, rarely 6.0). Mountain hemlock is classed as tolerant of shade but easily takes full sun.

Rooting Habit- Mountain hemlock is usually shallow rooted. In British Columbia, roots are mainly confined to the forest floor; this is not surprising because of the high proportion of soil nutrients in the forest floors of these forests. Mountain hemlock can root adventitiously slowly overtime and can grow in organic wetland areas this way.

Brief Work and Bonsai Bio-

Graham J. Hues RPF – Work:

I’ve worked in the forest industry for 38 years and have been a professional forester since 1994. My work has taken me all over Coastal British Columbia and exposed me to some magnificent forests and the many challenges of forest management on an assortment of different ecosystems

Currently I work for a large forest products company and as an obligation through the terms of the license agreement (with the province of BC) the company is responsible for stand and landscape-level planning including; Forest Stewardship Plans, Land and Resource Management Plans, Sustainable Forest Management Plans, Silviculture Investment Strategies, Mountain Pine Beetle Mitigation Strategies, Climate Change Adaption Strategies, Community Wildfire Protection Plans, Wild land Fire Management Strategies, Forest Health Strategies, Access Management Plans … etc


I’ve been active and serious with Bonsai for the last 8 years. Along with my friend and mentor we started up a local Bonsai Club in the fall of 2009, which has 22 active members (2013) and 4 of them bring much needed advice, knowledge and experience having been involved in the hobby for many decades.