Tsuga canadensis

Canadian Hemlock aka Eastern Hemlock, Tsuga canadensis as Bonsai

This is the first tree I ever collected, over eight years ago now. The development of this tree has been one step forward, two steps back. There is limited information out there on T. canadensis and I’ve only seen two that could be called bonsai (this tree  isn’t one of them). This is probably for two reasons: 1) it is hard to find worthy material, and 2) they are a quirky species to work with.

Eastern Hemlock are unique for a number of reasons:

  • They very, very much prefer a rich and moist organic growing medium. I almost killed mine by transplanting it into a coarse, inorganic medium. Replacing it with topsoil restored the health of the tree.
  • They can tolerate practically any light condition from full shade to full sun. For bonsai development, several hours of direct morning sun is good for promoting backbudding and branch development. Full direct sun tends to cause the foliage to lose it’s rich green colour.
  • Despite their delicate and almost “weak” appearance, they heal over wounds better than any conifer I can think of and better than many deciduous trees. This makes grafting easy on T. canadensis.
  • The branches are very flexible however they are extremely weak at the crotches. They will suddenly and heart-breakingly tear from the trunk with little notice during heavy (or even moderate) bending operations. However, their capacity to rapidly callus over wounds means that a branch will more often than not survive, even if you have torn half of the base away from the trunk.

I have learned and re-learned these points “the hard way” on this poor specimen over the years. The resulting setbacks have probably doubled the time it should have taken me to get to the current stage of development. Now this tree has immense sentimental value to me despite being one of the last trees that draws the attention of any visitors to my yard.

I believe Eastern Hemlock is by far the most delicate and feminine species native to eastern North America, and perhaps even all of North America. This makes it priceless in our catalogue of native species and worthy of greater attention. I just wish material was easier to come across!

My T, candensis today after finally getting the main structure set into place after eight long years.

My T. canadensis today after finally getting the main structure set into place after eight long years. Still a long way to go but I think the hard work is done. 

Last summer I was trying to fully style the tree and had to stop at this point after I tore a major limb that supported two major branches - the first branch on the left, and the back branch,

Last summer I was trying to fully style the tree and had to stop at this point after I tore a major limb that supported two major branches – the first branch on the left, and the back branch.

The tear in the limb last summer. Remarkably, the more important branch (second primary branch) survived despite losing much of the secondary growth. The back branch completely died

The tear in the limb during last summer’s work. Remarkably, the more important branch (second primary branch) survived despite losing much of the secondary growth. The back branch completely died

Growing near a trail in April 2007.

Growing near a trail in April 2007.

Collected and potted up showing the current front.

Collected and potted up showing the current front.

Overwintering Bonsai in the Toronto Area USDA Zone 5-6

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I’ve received quite a few emails from people asking about overwintering hardy trees outdoors. While there is lots of good information out there on the internet, most of it is region specific. What applies in England, Japan, or North Carolina does not apply in Toronto. With that in mind, this information is specific to zone 5-6 and is for people who have no special facilities (heated garage, polyhouses, etc.).

Reiner Goebel of rgbonsai.com has a good article about overwintering trees in the Toronto area. Have a read here. What I do is very similar.

  • Use tough species to make life simple. Semi-hardy species (Trident maples etc.) require more attentive care in this climate. My collection consists of Eastern White Cedar, Larch, Juniper, Yew, Siberian Elm, Potentilla, Ginkgo, and  few others. All fully hardy.
  • Don’t be afraid to leave them on the bench through a few late autumn frosts. They can take it. I usually put mine away in late October or early November. If the ground is frozen, you’ve waited too long 🙂
  • Bury the pots in the ground in your garden and water everything really well. This insulates the roots. The risk is not the rootball freezing. It can and should freeze solid. The tree will be fine. The risk is frequent freeze-thaw cycles. This is why unusually warm winters are more of a concern to us northern bonsai growers than unusually cold ones. Burying the pot helps ensure that once the rootball freezes, it will stay frozen until around March, even if there are some freakishly warm days in January (it happens). If your tree is in a massive training box but is a hardy species, just sit it on the ground and mulch around it. Just having contact with the ground will help buffer the rootball temperatures.
  • Snow is your friend. As soon as fluffy snow hits the ground, shovel it onto your trees (don’t shovel on heavy wet snow!). Sure, three feet of snow can bend branches but I feel most comfortable when my trees are buried in snow all winter. This protects from -20 degree air temperatures and drying winds. But when the snow starts to melt, brush it away as this heavy slushy mess can really cause damage to branches and fine ramification.
  • Try and winter them in a shady spot in the garden protected from the wind (i.e. a north facing corner). This provides a bit of insurance against wind and sun if it is a snow-less winter (like the infamous winter of 2011). It also helps keep the tree dormant as far into the spring as possible. This is important. If your trees break dormancy too early, the tender new growth will be exposed to the unpredictable early spring weather.
  • Rabbit-proof your garden as best as possible. When rabbits get hungry in the winter, bonsai bark apparently looks quite appetizing. Even  a couple of exploratory nibbles can ruin the image of a tree. Try to board up any gaps under the fence.
  • If you have the energy, fence in your trees with hardware cloth to provide further protection from pests. Burying the fence a couple of inches provides me some reassurance against mice, although if mice want to get anywhere bad enough, they will find a way.
  • Don’t worry about watering! If you put them away late enough, they should not need any water the entire winter.
  • Again, keep them dormant as long as possible. Don’t take them out of the ground at the first sign of spring in March. You know that in our part of the world it is not impossible to have freezing nights in May, and these spring freezes can kill off tender new deciduous growth.

This approach has worked well for me for 8 seasons. There are many ways to do it, but I find this to be the simplest and most foolproof approach. It takes some time to prep the trees for winter, but once they are in the ground you can literally forget about them, sit back, and wait for repotting season to come! Unfortunately, since the trees are frozen solid in the ground, you cannot really work on them in the heart of winter.


Head Scratching Re: Eastern Hemlock

Happy to report that I think I solved the health issues this tree was having over the last couple of years. Replacing the bonsai soil with mucky top soil seemed to bring it back to its former vigor.

Now I’ve got a new problem – I’m not sure which of the two trunks to keep. You’d think I would have figured it out after 7 years of contemplating.

    Today before work. It is on its second round of growth which is much better performance than in recent years.

Today before work. It is on its second round of growth which is much better performance than in recent years.

    For the last 6 years I have been planning to base the tree around this trunk. I even grafted a primary branch on with this front in mind (first branch on the right). The tree would be tall and upright with long downward drooping branches. Very simple but elegant, and easy to achieve with the somewhat difficult growth habit of T. canadensis. But then the apex died setting this tree back yet again. I've wired up a new apex but it needs about 2 years of strong growth before it is where I need it to be.

For the last 6 years I have been planning to base the tree around this trunk. I even grafted a primary branch on with this front in mind (first branch on the right). The tree would be tall and upright with long downward drooping branches. Very simple but elegant, and easy to achieve with the somewhat difficult growth habit of T. canadensis. But then the apex died setting this tree back yet again. I’ve wired up a new apex but it needs about 2 years of strong growth before it is where I need it to be.

 

To use the front above, I would have to remove this entire secondary trunk. Or, I could keep it and make this the tree. This is my dilemma. This trunk has much more movement and to many it would be the obvious choice. But something about it is awkward and unattractive to me. I don't like the angle of emergence from the soil, and I hate the upper third. Plus I'm not sure if Eastern Hemlock would lend itself to such a dynamic design. It is very difficult to get movement into the branches - they do not take well to sharp bending. The nebari is better from this side, however.

To use the front above, I would have to remove this entire secondary trunk. Or, I could keep it and make this the tree. This is my dilemma. This trunk has much more movement and to many it would be the obvious choice. But something about it is awkward and unattractive to me. I don’t like the angle of emergence from the soil, and I hate the upper third. Plus I’m not sure if Eastern Hemlock would lend itself to such a dynamic design. It is very difficult to get movement into the branches – they do not take well to sharp bending. The nebari is better from this side, however.

Both options have their merits. I’m still undecided, so for now the tree will just grow.


An Eastern Hemlock Story and a Lesson Learned

Eastern Hemlock (Tsuga canadensis) is rarely seen as bonsai because good material is hard to find. They bark up slowly, and grow in shady protected environments where exciting stunted material is rarely found. I’ve only seen two really good pieces of Eastern Hemlock yamadori that impressed me. One is dead now, and I have been trying (unsuccessfully) to buy the other one for awhile. I’ve never seen a mature and refined T. canadensis bonsai.

This Tsuga was one of the first decent trees I collected, back in 2007. It was growing in a dark understory near a trail were it was getting battered and bruised by passing vehicles. It has the beginnings of mature bark which is a sign of some age. Ring counts on a cut branch lead me to think the tree is 40-50 years old.

It had a shallow root system growing in mostly leaf mold, and I took home a mostly intact rootball. It grew happily in the moldy compost for 3 years, sending out 3 extensions every season. The tree seemed very strong.

Then, I had the bright idea to try and get it in a training pot and some coarse bonsai soil. The tree HATED it. Its growth slowed down, and the apex started to die back. It almost looked like a fungal attack, but whatever it was I am convinced that it was a symptom of a more fundamental problem – the soil mix.

The lesson here it to grow T. canadensis in a fine, organic mix. It may be the low pH that they like. Many people know this already (see Nick Lenz Bonsai from the Wild 2nd Ed.) but I was stubborn and in a phase where I though “bonsai soil is better for everything”.

So this spring I raked about 80% of the bonsai grit out of the pot (without removing the tree). The root system looked pathetic. I packed in sifted top soil and hopefully this will help the tree to recover. If it doesn’t help, I am about ready to throw in the towel with this one.

As a side notes, T. canadensis heals over wounds incredibly well. For such a delicate conifer, you would not expect it. This makes them suitable for grafting. The first branch on the right near the top of this tree is a successful one-point graft.