Chinese Elm Repotting – Key Bonsai Practice

Repotting our trees is a key bonsai practice, and one that you must gain mastery of. Here is a summary of basic steps you’ll take each time you repot your trees:

  • Make sure you have all necessary tools and supplies, including prepared soil, before you start
  • Have a suitable space to work in – outdoors a bench is ideal, indoors a small bench or table and a large tub to work in will help keep the mess contained
  • Prepare the new pot if you’re changing pots; if not, you’ll need to thoroughly clean the existing pot, replace drainage screen and the tiedown(s)
  • Unpot the tree and inspect the root mass
  • Comb out the roots which will have coiled their way around the outer edges of the mass
  • Trim away the overlong roots and enough of the root mass to give room for fresh roots to grow
  • Make needed corrections to the roots, namely the exposed nebari roots that are part of your design
  • Add fresh soil to the pot to provide a thin bottom layer – slightly heaped in the middle
  • Place the tree in the pot
  • Tie the tree down once you’re satisfied with the placement
  • Fill in all around the tree and any spaces in the root mass; use a chopstick or other tool to work the soil in
  • Water thoroughly; allow to drain; water thoroughly a second time; newly potted or repotted trees with fresh soil will need to be watered more frequently than others, as it take a while for the fresh soil to become properly wetted
  • Fertilize (this is optional at this time, but I tend to forget as I move on to other trees, so I go ahead and do it at the time of repotting)
  • Place moss on the surface if so desired.

This is today’s subject, the Chinese elm that has its own Progression page.

It was last repotted in 2018, and though it could probably go another year without it, there are a couple of issues with the nebari that I want to correct before they get out of hand.

This is one of the roots that I’m unhappy with. Though it’s grown well and is about healed from the previous pruning I did, it’s just too straight and untapering a surface root to remain. I can solve this problem as part of the repotting process.

This one’s a little harder to see, but the surface root at the left has a smaller root coming off it that runs at an angle back toward the base of the tree. It’s also too long without taper and needs pruning back.
Step number one, the tree is pulled from the pot. It’s at this point that you do the assessment of the root mass. Look for any root rot caused by poorly draining soil. Always cut away any dead roots – you can’t eliminate all the fungal pathogens by doing this, but removing the dead roots and using free-draining soil when you repot will allow the tree to recover on its own (which it should do). Expect to see fresh white feeder roots when you inspect the root mass. This is a good sign, of course. Don’t worry about trimming these off as a necessary part of pruning the roots to make the mass more compact; the tree will happily grow new ones.

I combed out the root mass, trimmed away some of the excess roots, and washed off the excess soil that I’ll be replacing. It’s easier to see root problems once you get to this stage. In this case, it’s a root that’s coiling back toward the trunk base. These should either be removed entirely, or if you need a root that’s grown this way then gently uncoil and trim it so it grows in the desired direction.

Here I’ve pruned that first of my large offending surface roots. I’ve also removed the coiling root that I don’t need since I have a good mass of roots to support the tree.
In this photo you can see that I’ve pruned back the large root even more. My goal is to build the taper of this surface root. By pruning it back, I can expect the roots already branching off this one to continue to thicken over time. That should produce the effect I want.
Here’s the view from the other spot where I have that odd root moving back toward the trunk. There’s obviously work that needs doing.
The offending root is gone, and I’ve pruned back the too-straight surface root as I did the other one. I’ll be able to build taper with this one as well.

Here’s the tree after the final root trim. I’ve removed about a third of the total root mass, which is the right amount for this repotting. The amount of root mass you remove will vary based on how long it’s been since the last repotting, and how much root the tree has grown in the interim. With experience you’ll be able to immediately gauge this as soon as you pull the tree from the pot.

Here I’ve placed the tree back in its pot. I previously washed the pot thoroughly, made sure the drain screens were in good shape, and replaced the tiedown wire.

Placing your tree in its bonsai pot requires you to consider several parameters to ensure the composition is its best. They are (in no particular order):

  • Determine the correct placement of the trunk base – in this case, since my tree emerges straight from the soil and terminates left of center at the apex, the base needs to sit slightly toward the right side of the (oval) pot
  • The tree also needs to sit slightly to the rear of the pot
  • The tree sits on a slightly heaped mound of soil, which brings the base just above the rim of the pot
  • I had previously selected this pot because it is, in profile, roughly as deep as the trunk base is wide
  • The pot measures about one-half the height of the tree in length, making for a good proportion
  • The initial portion of the trunk emerges straight from the soil; the planting angle needs to be such that the initial portion of the trunk is perpendicular to the pot rim.
The tree has been tied down (I use a single tiedown for most of my bonsai; use however many work best for you), and the pot filled with soil. This step requires a lot of care. You can’t leave any gaps beneath the surface of the soil, because that spot will dry out and any roots there will die. Most everyone uses a chopstick to work the soil into and around the root mass. Some will say never to jab the chopstick into the root zone when you do this; I’ve never found this to cause a problem, since there really aren’t that many tender roots present at this stage of the process. If you’re concerned, then you can carefully insert your chopstick and wiggle it back and forth to work the soil in.
Here’s a closer look at the nebari. I’ve improved the surface rootage quite a bit, and this should result in a much better bonsai in a fairly short time. This tree has been in training since 2014, so the next few years should complete the making of this Chinese elm bonsai.

The final presentation for today. I did a little trimming of the branches (there’s probably a little more to be done), then watered and placed some moss on the surface. I also added some time-release fertilizer so I don’t get busy with other trees and forget. Because I’ve done root work on this tree today, it’s probably going to start opening buds within the next week. I have a lot of small Chinese elms in gallon pots, and most of them area already leafing out. Spring is getting closer by the day!

Let me know what you think of this repotting job.

Water-Elm #35 Video #2

This is one of the Water-elms I collected on August 4th. I really liked the natural but artistic look of the clump (not all clumps are worth working on, trust me). I knew I could make something really special out of this one.

In two months’ time this tree has put on so much growth that I know the root system will allow me to slip-pot it without any concerns. And that gives me a head-start on its development as a bonsai.

Here’s how I did the slip-potting. One of the things to keep in mind when you’re collecting trees is the bonsai pot that lies in the future. The roots of the tree must fit that pot, and that means not only the radial roots but the tap root as well. Be sure to chop it short enough so that the tree fits “comfortably” in the pot. You don’t want to do that chop but once.


The pot I put this tree in is a beautiful handmade piece by Lary Howard.

I’d love to know what you think of this bonsai to be. Leave me a comment below.

Bonsai Odds & Ends – May 22, 2016

When we create and maintain our bonsai, we never work on them every day. No matter whether it’s potting, wiring, pruning, or even pinching, bonsai is a “go and stop” endeavor. This excludes watering, of course. I highly recommend you water your trees daily (this is a joke, of course; water your trees daily when it fails to rain, or your bonsai will truly be finished works of art).

And so, the creation process involves many steps and decisions. Beginning with the bare but terrific trunk, which I do most of the time, you have to build the tree structure from nothing. This means trunk buds that become shoots, shoots that get wired to shape in order to make them into branches, branches that thicken and subdivide into sub-branches, leaves that start getting smaller as this process continues; a new leader that is wired and positioned, then extends and thickens, then gets cut back with a new leader that extends and thickens, rinse and repeat as many times as needed, then apical branches developed from buds that become shoots that get wired and positioned. Whew!

As you build your bonsai, you make decisions based on the stage of the tree’s development and your knowledge of the tree’s growth habit. Here’s an example of this concept. I repotted this American hornbeam, Carpinus caroliniana, earlier in the season, and also did some carving to enhance the trunk:

Hornbeam3-1-16-1Collected in 2010 and having a massive trunk, this hornbeam was destined for a lengthy development period in order to thicken the tree’s branches. There must be a good proportion between trunk thickness and branch thickness, otherwise the eye/brain does not believe the illusion. Trees in the wild grow their branches in correct proportion to the thickness of the trunk, because … well, just because. No bonsai artist is out there interfering, and barring some other human meddling they just grow how they’re supposed to. The lowest branches tend to be anywhere from 1/4 to as much as 1/2 the trunk thickness at the point where they emerge. When making bonsai, this is one of the basic challenges and cannot be ignored.

Hornbeam3-5-16-11Here’s the after shot from the repotting. The carving that needed doing got done, and the tree got some fresh soil (American hornbeam roots very vigorously in a bonsai pot). I also re-exposed the surface roots, which are coming along just fabulously.









Here we are, just over six weeks later. The rampant growth is obvious, and it helps to point out the fact that hornbeams are not apically dominant trees. This means you can usually develop side branch thickness as quickly as you can new leaders. Not a bad feature.

So what to do with this tree? I decided it just needed a haircut, nothing more dramatic. This coming winter I’ll cut the tree back harder, so the ramification will improve in 2017.







And after. The tree still looks somewhat disorganized, but that will change once I do the hard pruning and really tighten up the foliage. Hornbeam (and other species) like to push their shoots as far as they can. For apically-dominant species, this is to help the tree grow taller faster. For non apically-dominant trees, it’s to increase spread and the tree’s ability to gather sunlight to manufacture food.








Here’s an updated photo of my awesome willow oak, Quercus phellos. It was time for a trimming, plus I needed to do some work on the lowest two branches. I decided I didn’t like the straight, boring though thick lowest right branch so I cut it off in winter. Unfortunately, it didn’t bud back so I’ll abandon it for two new shoots. You can see I’ve wired them into position.

I also cut back hard on the first left branch, to continue building taper in it.

I probably won’t do any more trimming on this tree in 2016, unless a branch in the crown starts getting too strong. Those are coming along well, I just need to build ramification.

I’d love to hear what you think of either of these trees.


“* Dragon *” Throws Buds

Water-elm10-24-15You first saw this water-elm on August 16th. Dimensionally, it’s the biggest I’ve ever collected, sporting a trunk base 6″ across and measuring 42″ along the length of the trunk (but only 28″ in height from the soil surface). In terms of character, I’ve never collected anything better. It’s no exaggeration to say this is a very significant water-elm pre-bonsai – in size and style, certainly rare if not unique.

If you consider most examples of this species, the typical form for less than fully mature non-primary specimens is bush-like (water-elm does not get more than about 40 feet tall). Smaller trees tend to have two or more trunks. This form persists as they get larger, but you typically see one large trunk, one or two that are somewhat smaller, then one or more whip-sized trunks emerging from the root base. This makes collecting both exciting and challenging, as you don’t necessarily want everything to be multi-trunk. And it’s for this reason that I’m always excited to find a single-trunk example. Cathy found this one, and I was stoked. I have no idea what happened to it, but it was growing near a heavily traveled swamp road and most likely was run over by a truck untold years ago. Forced over, damaged, it nonetheless grew on.

I’ve mentioned in a previous blog post that my August collecting efforts were not as successful as I would have liked. It’s just one of those things that happens, tough to foresee. Despite this, about four weeks ago I noticed roots growing across one of the drainage holes of this tree’s nursery container. That was all I needed to know. I was sure this amazing water-elm specimen was going to make it.

I’ve pretty much ignored the tree over the past month. Along with everything else, it got watered three times a day as we’ve had mostly warm weather through mid- to late-October. But nothing more.

Today I was shocked to see a shoot pushing right near the chop on this tree. It was something I really didn’t expect, despite the fact that I knew this tree had made a lot of roots over the past couple of months. I figured it would simply wait until Spring 2016 to bud out.

So we’ll see how much growth we get before the inevitable cool-off happens, then it’s on to winter and the long wait till April when water-elms bud out. Assuming all goes well, I should be doing an initial wiring and shaping by early May. You’ll see updates as the tree progresses from collected trunk to bonsai.

And of course, it’s absolutely a requirement that this tree needs to have “Dragon” in its name. I’m not sure if it needs anything else, but that part is settled.

Let me know what you think of this tree.

A Year In The Life Of A Water-Elm Bonsai

I’ve mentioned before that one of the fall chores we can do that has a key effect on how quickly our bonsai develop is fall pruning and wiring. While we can’t expect much growth on our trees at this time of year, we can make and implement vital design decisions. Now, there are certain chores I don’t recommend in the fall. An example is trunk-chopping. The reason I don’t recommend this is the tree responds according to its “programming,” meaning it wants to replace the trunk and foliage mass you’ve removed. New vegetative shoots will do their best to form and grow out. This is certainly well and good, but all too often you run headlong into your first cold snap which means the new shoots don’t have time to harden off. If they subsequently get killed off by cold weather, your tree can easily suffer dieback.

Water-elm5-9-15I collected this water-elm, Planera aquatica, in August of 2014. It sprouted just a few weak shoots near the base a few weeks after collection, but that was it. I figured the tree wasn’t going the make it, but I also realized that the collecting season had been delayed last year just as this year’s was. There wasn’t really any reason to assume the tree had dried out, since I take great pains to seal up my trunk chops. So I left the tree alone, and sure enough it came out strong this past spring. I ultimately decided to keep this tree, considering how many I had lost in Winter 2014.

This first photo is from May of this year.







A month later I decided to do the initial wiring and pot the tree into my vintage Richard Robertson oblong lavender pot. I felt the elongated pot matched up perfectly with the tall, graceful trunk. The tree has a tremendous flaring base with great surface roots, which is about the best start for a bonsai you can expect.








I’ve been practicing one of my key training techniques, benign neglect, on this tree for the past three months. Aside from unwiring branches to keep the wire from biting in, I’ve only fed, watered and kept a casual eye on the tree. It’s done the rest. What a wild result, eh? But this is just what the bonsai artist needs in their trees that are under primary development.









I’m posting this close-up so you can see how quickly the new leader has thickened this year. From trunk bud to 1/2-inch diameter in a single growing season. The secret? Wire a little movement into it and let it grow!







And here’s the tree after wiring and pruning. I took off a good bit of the leader, but refrained from cutting back too far since I won’t get much more growth this year and the shoot is still very young. I’ll cut it back harder in spring and wire up a new leader in order to ensure the tapering is done right.

And that’s a year in the life of a (new) water-elm bonsai. This tree will be showable in two more years.

Bonsai And August

Do those two words actually go together? Can you do anything in August besides water your trees and watch them endure the heat? The answer is a qualified yes. To be sure, you don’t want to go root-pruning and repotting your deciduous trees in August. Though I don’t grow them, I understand junipers can be worked on in August. But in the part of the bonsai world I inhabit, there are limited things I get to do – but very important things, nonetheless. I can do a late summer wiring of trees I unwired earlier in the summer due to swelling of branches. I can do some pruning of overlong branches. I can cut back an apical shoot that has done its job for the season. In other words, I can work on the fundamental design of my trees, in anticipation of next spring.

I can even do an initial wiring, for example on this trumpet vine, Campsis radicans:

Trumpetvine8-29-15-1The new tendrils have grown out and are now sturdy enough to wire. I still have to be careful when doing so, but I know as long as I don’t flex the tendril at its base I won’t have any trouble.











This was fast work, as I only had three “branches” and the new leader to wire. But this bonsai-in-the-making now has its basic shape. This is one of the really great things about the art of bonsai: making the most out of not so much. In this case, I can express an entire mature tree in nature in only four shoots.

What’s next for this specimen? It’s in the process of storing food for the coming winter. Trumpet vine is deciduous, so metabolically the plant is only “thinking” about survival as it’s going to be dropping its foliage in about six to eight weeks. As for me, my only chore is to keep it watered and watch the wire for any signs of binding (which I don’t expect).



This water oak, Quercus nigra, has really taken off for me this year. Fast growth, properly managed, is just what you want when developing your bonsai. Fast growth means fast branch creation, fast crown formation and fast ramification. In the case of this tree, I’m building it completely from the ground up so fast growth is allowing me to build taper and branching. There are two primary efforts going on simultaneously with this tree: one is creating a tapering trunk, and the other is establishing the basic branch structure as I go along. Now, with this specimen you’ll notice that my first three branches are fairly close together. This would certainly be all right for a shorter tree, but I’ve decided this one needs to be on the order of 16″ tall. Because of this, I can’t leave all of the low branches. I have to select a first branch, then prune accordingly.


Wateroak8-29-15-2Now I have only one low branch, which is in a good position to be my first branch. It’s about six inches from the soil surface, so if my tree ends up being 16″ tall it’ll be in just the right spot.

Notice I’ve also clipped the leader. It’ll be cut back farther next spring and a new shoot selected to run wild, continuing the process of building the trunk. I left it overlong so there won’t be any risk of dieback during winter.