This is why we prune.


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Occasionally I witness a beautiful example of why we do what we do in bonsai. I’d like to share just such an example, highlighted by the plant itself.

Four weeks ago, I cut back this unremarkable boxwood. Perhaps more important than what I did four weeks ago what what I DIDN’T do in the weeks before that. I DIDN’T prune until the new growth had extended and hardened off.

As you may be able to see in the image above, the new growth had extended to several pairs of leaves. Allowing that growth to do its thing and strengthen the plant before cutting, produced the result we are looking for – new branching!

This is how the plant looks today. The branch on the left will be removed at a later date, so the growth was not pruned. What we need to note is that this branch has not pushed new growth like the rest of the tree on the right.

Those dark green leaves are from the first spring growth. They have hardened off and now display a darker color than new growth.

In this top view of the right-hand branch that was pruned you can see fresh, light green leaves popping out everywhere.

Repeating this process over time – allowing the plant to extend and build strength, then cutting back to promote more branching – is how we can develop a tree with lots of branching.

What we must avoid is cutting too soon. If we cut the growth as soon as it extends, that branch won’t be able to gain strength or build up more strength in the tree. This vigor is needed to push new branches.

The same process has been occurring on this faster growing Vicary privet. In fact this tree has been pruned hard twice already this year, and today was number three! The image above was before pruning, and below is after.

This tree is in a branch development phase with sacrifice branches as well, so it doesn’t have a strong silhouette yet, but being able to cut back multiple times a year will help me develop a lot of ramification in this tree. I’m excited to see where I can get it in another year!


August Ficus Work

A friend of mine shared that August 11 (an oddly specific date) is the “perfect time to repot ficus.” I’m not sure exactly where he got that info, but coupled with the familiar “hottest day of the year” advice, I will conclude that it is not too late to repot two small ficus I have been meaning to get to.

Both trees are very early in their development. The first is this Ficus microcarpa which I have dubbed “Captain Jack.”

Jack has been allowed to grow out a fair bit, but I’d like to start working on developing a branch structure. I already lost an opportunity to develop some branching by letting it grow out too long. You may be able to see, in the image above, that some of the long extensions began branching, but all of those are too far away from the trunk to be useful.

To begin developing the primary branches, each branch coming off the trunk was cut back to just two leaves. Only a couple had some close-in branching that could be kept. In those cases, each growing tip was reduced to two leaves with hopes the bud at the base of each leaf will extend into a new branch as it grows out.

I cut each remaining leaf, leaving the petiole and just a small triangle of the leaf blade. These will serve as dramatically reduced, but still functional foliar surface area to sustain the tree until new leaves push out.

The second tree is a small Ficus salicaria that has also grown out significantly.

The large branch reaching to the right, in the photo above, was removed, and a similar approach to the first tree was applied to what remained.

Perhaps contrary to the evidence above, I have declared on multiple occasions that “I am trying to quit tropicals.” I have only a small collection of ficus, but each has a special value to me because of where it came from or how long I have had it. When I say “I am trying to quit,” I really mean I am just not adding more ficus to my collection. Nevertheless, I couldn’t bring myself to throw away the thickest branch I removed.

Salicaria root so easily, and they really are a great variety to work with. I will just plan to give this cutting away to someone who can develop it. Who wants it?

Bonsai Watering: Another Perspective


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As an educator, I have always held a deep appreciation for a new or different perspective to understand an idea. I admit, when faced with a student who didn’t understand what was going on, I have repeated the exact same words I said a moment before (no doubt with more sarcasm than belongs in a classroom). I hope this was only at times when the student just wasn’t paying attention, because if the student didn’t understand something because of the way I explained it, they deserve an opportunity to hear it in a different way.

With this as background, then, I was very excited to hear a whole new way of thinking about the most basic and essential of bonsai skills: Watering. More than just watering though, this was about the relationship between watering and the choice of soil components.

Now, don’t assume I just mean, “different soil, different watering requirements.” It is that, but so much more. This was a new way of thinking about how often we water, how often we WANT to water, and what type of soil allows us to do that.

I had the pleasure of joining a tour of the National Bonsai & Penjing Museum led by the curator, Michael James. I got the impression Michael enjoyed the opportunity on this occasion to give a tour, not just to visiting public, but rather to a group of bonsai enthusiasts — members of the Northern Virginia Bonsai Society (NVBS).

Among many topics we were able to explore, Michael explained watering this way (Michael, I hope I do not misrepresent your words):

It’s all about the balance of water and oxygen in the soil.

Check. This is not new to me.

When we water we throw the balance to one end — too much water. As time passes, water decreases and oxygen increases until it gets to be too much oxygen, not enough water.

Ok, I follow.

Each tree/species has a sweet spot…

Wait. What?!

Each tree/species has a sweet spot — a best ratio of water to oxygen when that tree can grow at its optimum level. That sweet spot is somewhere on the continuum between too much water and too much oxygen.

Huh! Makes perfect sense, but this is kinda new. Then he said this.

We want to move each tree through that sweet spot as often as possible. At least daily, a couple of times a day if possible.

Do you see a new way of thinking here? Consider what this means.

It certainly means every time we water too soon we deprive the tree of an opportunity for optimal growth. It also means every time we put watering off longer than necessary, we delay the next opportunity, but let’s think about what this means for soil.

If we use a soil mix with fine particles and organic matter that allows us to water only once every few days, we are only giving our trees the opportunity for optimal growth once in the span of those few days. If, however, we use an inorganic, fast draining soil mix (such as a mix of akadama, pumice, and lava recommended by so many professionals) that requires us to water daily, we are setting up our trees to experience optimal conditions far more often.

Now, listen, I’m not saying this will dramatically change anything I am doing in my garden. It may make me think twice about whether it’s the right time to water, but I have that conversation with myself daily anyway. What’s important to me is I feel like I have a new perspective, and perhaps a deeper understanding of this essential component of bonsai.

And maybe someone else out there will start using a different soil mix and have healthier trees as a result. Win. Win.

Virginia Pine Angle


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In the spring of 2017 I collected the Virginia pine, Pinus virginiana, pictured multiple times, below. I love the bends and curves in the trunk but have, to date, focused on its health and recovery and have not decided how to take advantage of those curves to make a nice bonsai. It has been doing exceptionally well so I thought I would give some consideration to the future design starting with the planting angle.

I’m sure it’s difficult to see, but from this side, above, the trunk comes toward the viewer and hides it connection with the soil, so this side is pretty much out.

I played with the angle, above, considering a design that would drop the trunk line down in a cascade before turning back up again. I pushed it a little further by rotating the camera to imagine a steep drop as in the image below.

Ultimately, I think I have decided on the angle in the last tree photo, below. This position places the hardest bend directly above the base and creates an interesting diamond shape that I think will work nicely.

It may take a long time to work this into a finished design, like the sketch at bottom, but this decision will help guide any pruning and wiring that are done, even if before it is replanted at this angle.

Thanks to Owen Reich for helping me thing through some possibilities. I will be sure to share any updates when I do work on this tree over the coming year.

The Hottest Day


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Have you heard the suggestion to “repot your ficus on the hottest day of the year”? Well, it was cooler today than the last few (only the low 90s F), but it was so brutally hot AND HUMID the last few days, I was not about to work in the garden.

This is the subject of my work today: an exposed-root Ficus benjamina I have had for over 20 years. Step one is selecting a better pot. The brown rectangle in the image above fits the root base nicely, but the color does nothing for this evergreen tropical.

The blue isn’t much better, and the shape is very similar to the original.

The teal is even better and the soft round corners suit the tree I think. But check this next one out!

Me likey! The size is good, it’s got curves, and the color, though muted, compliments the bark. The significant difference, however, is the depth. The shallower pot really lets the boldness of the exposed roots shine. This is the one!

I did the repotting first, and adjusted the front slightly. Next is a full defoliation. This will force the tree to push a new flush of leaves that will be smaller than the ones I just removed. With ficus, I sometimes cut the leaf leaving a bit of surface area so photosynthesis can continue while the new leaves develop, but this time I only left the petioles (leaf stems).

With the leaves removed, I have a clear look at the branches that need to be shortened, and others that could use some wire.

With some care, and a little luck, I hope this will be in good shape, with a full canopy for the fall show.

Boxwood Bonsai Clean Up


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This shohin size boxwood has had plenty of time to harden off spring growth and gain strength and energy from those fresh leaves.

The goal for today is to clean out the structure of old and unnecessary leaves and cut that spring growth back to one or two pairs of leaves. These steps will allow more light to reach the inner branches and set the tree up to set strong buds for the next round of growth.

Above is an example of a branch with far too many extra leaves. Plucking leaves from the old wood areas and from the base where new branches emerge will allow more light and reveal the branch structure. The same branch is shown below after plucking.

We often hear that we should remove branches that are growing down, but with the dense leaf growth of boxwood, I also like to remove individual leaves growing off the bottom of branches.

Compare the image above with the ‘after’ image below. Those leaves were less efficient by being shadowed under the branch, and removing them really cleans up the presentation of the branch.

I’m not making any big cuts or doing any wiring today, but these same steps should be done before either of these procedures. This will allow clear visibility of the branch structure, so choices can be made in removing branches, and provide a space to transition wire at the crotches.

After some careful leaf plucking on the whole tree, I prune off several leaf pairs from each branch of new growth making sure that the last pair or two of leaves left behind are from this season’s growth. This is usually easy to determine as the stems of the current year’s growth will be green while last year’s growth will show some lignification.

That’ll do. Now it’s back on the bench.

Can Bonsai Do Math?


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I don’t recommend asking your bonsai for help with your calculus homework, but if you treat them right, your pine branches sure can multiply!

I have only been decandling this unimpressive Japanese Black Pine, Pinus thunbergii, for three years. We are not here to talk about the design. We are here to talk about ramification and needle reduction.

In 2016, the first time decandling this tree, I removed 30 candles. One year later, in 2017, there were 57. And today there were 113. That’s just one candle shy of a perfect doubling!

The candle size is further proof of concept. The first year, the candles ranged in size dramatically.

Range of candle sizes in 2016

The candles this year are much smaller, and very consistent in size.

Candle size in 2018

So what am I doing?

  • Feed for the whole growing season.
  • Remove all candles at the same time. (I do this in the last week of June or first days of July in Northern Virginia. The right timing will vary by location and climate.)
  • To balance growth, pluck needles behind each growing tip to the same number of needles per tip. (Growth will be stronger with more needles and weaker with fewer remaining.)
  • As the second flush emerges, reduce to two new buds/candles per growing tip.
  • In the winter reduce to one bud per tip.

All of this is based on my best understanding of decandling from a variety of sources. If you are just getting started understanding decandling of black pines. Check out Bonsai Tonight. There is a wealth of information there!

Developing Deciduous Bonsai


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Do you ever have those moments when you learn something new and want to run right out to the garden to apply it? I finally got around to listening to the Asymmetry podcast with Dennis Vojtilla. If you have deciduous bonsai you should give it a listen! Dennis is a deciduous genius and he shares several concrete tips in his interview with Ryan Neil of Bonsai Mirai. Listening made me realize I have several deciduous trees that are due to be cut back.

The one I was able to tend to this evening is a very young plant, so it is hardly a refined specimen, but I thought I’d share it nonetheless.

This Korean Hornbeam, Carpinus coreana, was given to me by Steve Miller as a 2-3 year old seedling a couple of years ago. I guess that makes it only 5 years old. Even in this small pot, it is growing well and is definitely due to be cut back. Today I am cutting back to two leaves on each new branch.

If you listen to the podcast referenced above, you will hear Dennis recommend cutting back to one, but I am going to assume he is talking about trees that are far more refined than this!

Cutting back this hard after letting the branches harden off, as I have, should result in buds at the base of (hopefully) both of the remaining leaves push out. This will mean twice as many branches which will, over time, create a nice full tree.

You can see that the pile on the left now has far more leaves than the tree, but I am confident the tree will grow well and be just as strong in a few weeks.

I’m not too concerned about the design at this early stage of development, but I might be tempted to repot it to the angle shown below next spring. What do you think?

Quality Time at a Quality Site


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I had the pleasure of spending most of the day at the U. S. National Arboretum and Bonsai and Penjing Museum. The task at hand was setting up for (helping vendors set up for) this weekend’s Potomac Bonsai Festival. Lucky for me, there wasn’t a lot of work every moment of the day.

During one of those quiet times, I had the pleasure of helping my friend LeAnn prep a couple of trees for the PBA member show. The odiferous task was applying Lime Sulfur to the deadwood on those trees. Some complain about the smell, but I rather enjoy the task. It’s pretty much painting a tree. What could be wrong with that?! Besides, I got to do the work here…

…among the plants and trees “behind the scenes” of the bonsai museum.

Of course I also found some moments to enjoy the collection.

All and all, a beautiful day. I look forward to more days like it this weekend. Come on out, see the trees, and check out the vendors. For more information, go to the PotomacBonsai website.