Naturalizing a Japanese Stewartia

In 1995 the Arboretum hosted a visit from the popular American bonsai artist Chase Rosade. Among other activities, Chase conducted a workshop wherein students made forest plantings out of two and three-year seedlings. He had bunches of very young plants of differing species, and at the end of the class he had three Japanese stewartias (Stewartia pseudocamellia) that weren't utilized, so he gave them to the Arboretum. I grew the little trees for a couple of years without doing anything to them because starting out they were no bigger in diameter than a pencil. Eventually I decided to take two of them and put them together as a twin-trunk planting. I used the largest of the three stewartias along with the smallest so there would be some appreciable difference in size, and then decided to be clever about it. I wanted to be certain the two trees stayed "married" to each other, so I joined them together at the base using a drywall screw. All this took place before I developed better habits about photographically documenting the history of each plant in the collection, so I have no pictures to show of any of it.

This is the first image I have of this specimen, taken in April of 2008:

It’s plain to see the trees are still very young, but they have made some progress from where they started thirteen years earlier. They have fused nicely at the base where the two were joined together. These next images are from autumn 2009, and show the twin-trunk stewartia on display in the bonsai garden while transitioning through its autumn coloration phase:

Images made in summer and winter of 2010:

The twin-trunk stewartia in spring, summer and autumn of 2011, on display in the garden:

There is so much to enjoy about Japanese stewartia — not just as a bonsai subject, although they are well suited for it, but as an exceptionally beautiful smaller tree species. They have large, showy, white flowers that make them extra alluring for a short while in the spring, and in the summer their leaves are refined looking and handsomely displayed. Stewartias also produce wonderful autumn coloration, buttery yellow aging to rusty orange, in the days leading up to leaf senescence. But all year long, and especially when they are bare in the winter, they can be appreciated for their beautiful, copper colored, exfoliating bark. There is everything to like about these trees.

The genus Stewartia belongs to an exclusive group of plants botanically known as the eastern Asian-eastern North American floristic disjunction. Stated simply, plant species belonging to a floristic disjunction are found only in two physically distant areas of the world and nowhere else. Paleobotanists attribute this phenomenon to the existence of land bridges long ago that once connected now distinctly separate continents. However it came to be, there are numerous genera of plants whose members are found only in eastern Asia and eastern North America, and Stewartia is one of them. There are only a dozen or so Stewartia species in the world and all but two of them are in eastern Asia. In eastern North America we have the silky camellia (Stewartia malacodendron) and the mountain camellia (Stewartia ovata), both of which are considered native to our region but are not often encountered in the field or in the nursery trade.

I mention the eastern Asian-eastern North American floristic disjunction because it was a subject of keen interest to my mentor, Dr. John Creech. Briefly in the very earliest years of our collection and program, the disjunction angle was considered as a possible justification for having bonsai at The North Carolina Arboretum. The idea was that our bonsai collection might focus on species belonging to the disjunction, but this strategy was ultimately rejected for being both impracticable and needlessly limiting. As it happened, the Japanese stewartia specimen currently under discussion is the only member of its genus represented in the Arboretum's bonsai collection.

Here is an image made in April of 2013:

The tree in summer of that same year, its last appearance in the bonsai garden:

If you look closely at the previous images, you may detect some differences in the habits of the two trees that make up this pair. These discrepancies were not glaring, at least not in the photos, but they were there and were more noticeable when seen in person. They were most evident at the two showiest times for this species — spring and autumn. The smaller of the trees was on an earlier schedule, so to speak, and would produce flowers first, and show the first signs of autumn coloration before the taller tree did and then went bare before its counterpart. The density and physical attitude of the foliage was also slightly different. It was not that one or the other was superior in its habit, but just that the two trees were different from each other. That lack of similarity looked strange on a twin-trunked tree. The problem, of course, was that it was not a true twin-trunk but a fabricated one. The clever lad who screwed the two young trees together did not take into account that they were seed-grown and therefore might have genetic differences that happened to be visually apparent. When the bonsai was immature and scrawny it did not matter so much. But as it began to acquire some of the better character that comes to an aging tree, the disharmonious look of its parts became more of a distraction.

Too bad, too, because the trees did a fine job of accepting their physical partnership. Over the years the binding screw was totally swallowed up and the bases of the trees completely grafted together. The two had essentially become one.

I had been for a while contemplating the removal of the smaller side of the arrangement, but was hesitant because the remaining trunk was so devoid of branching on one side. Then one of those small miracles happened — a little bud appeared on the larger trunk exactly where I would like to have a branch. I let it grow unmolested for a season just to make sure it survived and then I made my move. I cut off the smaller trunk and slipped the remaining tree out of the bonsai pot and into a grow box. This picture was made shortly afterwards, in January of 2014:

It was not my original intention that the smaller tree would be a sacrificial means to build a better base for a single-trunk specimen, but that is pretty well how it worked out. I chose to leave a little stub of the chopped-off trunk as insurance against die back. That stub was removed during the next growing season, and the callous to cover the wound soon began to roll in from the margins of the cut. The tree was pruned only once in 2014, sometime around the end of June, and I used the Walter Pall "hedge cutting" method. That is to say, I broadly carved back the upper part of the tree to a rounded silhouette, ignoring interior growth, taking little away from the lower branches and nothing away from the critical new branch developing on the weak side. The idea was to build strength in the plant after having removed the entire secondary trunk, and to encourage new branching with which to work.

This in-the-round series of images was made in January 2015, just prior to the next full styling session for this specimen (click on any image for full view):

January 2015, before

The next four pictures show the results of that 2015 session (click on any image for full view):

January 2015, after

At the time when this styling was done, I wrote about the Arboretum’s Japanese stewartia for an online bonsai forum. I posted the following diagram, including the interpretive text that follows it:

Zone 1 - This is the top of the tree, where most of the growth energy goes. Over the years, despite my knowing that this zone grows more vigorously, and despite my therefore always pruning it more aggressively, the branches have become too heavy. This is not at all uncommon among apically dominant species, and can be more of an issue with some than others. Because this specimen is currently undergoing other serious structural reordering, it seems to me an opportune time to address the problem. It is a problem because a tree with its heaviest branches up high will in time look imbalanced. Additionally, in a broad way of thinking, it makes logical sense that the heavier branches on a tree will be the lower, older branches, and the lighter ones the upper, younger branches (although it is easy to find examples in nature where this is not uniformly true.) So, some of the offending branches have been removed altogether and others have been pruned back to the point where there are no visible buds remaining. Familiarity with this species and with this specimen tells me that it is well capable of producing new growth on old wood, especially in the upper, more vigorous zone of the tree. Also, I have lowered the overall height of the tree by cutting back to what had been a lateral branch. That branch is now being hoisted up in a more vertical position by use of a guy wire pulling off the remains of the old trunk line. No padding is used on either attachment point because both pieces where the wire is wrapped around will eventually be removed.

Zone 2 - This branch is well developed but not so strong. The vigorous growth at the top of the tree has come, to some degree, at the expense of this important branch. While zone 1 took a major hit in this round of pruning, this particular branch was only lightly trimmed. Ultimately, it will be headed back and shaped up, but perhaps not until next year. The objective for the coming growing season is to have this branch grow strongly.

Zone 3 - This is the all-important new branch, which is destined to fill out the side of the composition left empty by the removal of the secondary trunk. It has been pulled downward with a guy wire and nothing has been taken away from it. My current thinking is that this branch will behave something like a second tree. It will not have a primarily horizontal orientation, but will partially ascend and provide perhaps a third of the total crown of the tree. This is a feature I frequently see in the natural example, but is rarely ever expressed in bonsai. Can that work stylistically? I think it can.

Zone 4 - This branch used to serve as the first back branch in the old composition, but in the new arrangement it will be too low. It is being grown now as a sacrificial branch to help build up the base of the tree. By allowing it to remain for the time being, it also helps to maintain the tree's overall energy level during this current round of pruning-induced stress.

So that is the game plan, at this point anyway.

Included with the article was a drawing showing the ultimate structural effect I had described and was hoping to achieve:

The stewartia responded well to the 2015 styling session, producing an abundance of new growth. The following year the same process was followed:

Several notable developments can be observed in the “after” image above. The lowest branch, which was left intact the previous styling session as a means of temporarily helping to maintain the tree’s overall health, was removed in 2016. The top of the tree was further reconfigured through heavy pruning and wiring. The whole tree, virtually every branch, had been wired, as was the case in several prior styling sessions, and as has been done repeatedly in the years since. This is worth mentioning because some people have the mistaken notion that naturalistic styling means letting the tree do whatever it wants. This errant idea arises, I think, from confusing the word naturalistic with the word natural. Growing a naturalistic bonsai is hardly more “natural” than growing a classical bonsai — both require heavy manipulation of the tree through the use of pruning and shaping with wire. The difference between those two styles has to do with intended effect and not with the means typically used to produce it.

Take note of the development of the lowest branch on the right side of the tree, which began as a fortunate bud-break just three years earlier. By 2016 that branch had gained enough size and visual weight to begin having its shape refined.

This in-the-round series of images from two years later shows developmental work continuing. Note the use of guy wires to put heavy directional stress on certain key limbs. The stewartia at this time was also repotted from the oversized wooden box to a stoneware bonsai container (click on any image for full view):

April 2018

In the above set of pictures, it can be seen that removal of the lowest branch the year before had been accomplished by means of breaking it off rather than cutting it flush with pruners or a saw. This technique belongs to the naturalistic school of thinking. The desire is to have the bonsai ultimately look like it styled itself, like the tree just grew that way as the result of natural causes. Trees in the wild lose limbs all the time, usually by having them broken off. When a tree limb breaks in nature there is always residual evidence of the event, in the form of a tearing scar on the part of the tree where the limb detached or in the form of a dead stub where part of the broken branch remained. Over time this stub rots away and the tree goes through a process of sealing off the wound. When a dead stub is left on a deciduous bonsai tree like this stewartia, the expectation is the same. Over time the stub will rot away and the tree will do what’s necessary to protect itself. The result will be a more authentic appearance for the scar that must inevitably result from the loss of a substantial limb. Take note that the big lower branch on one side of the tree — the branch being developed from the fortunate bud — has also been pruned by means of breaking off a substantial limb.

The following gallery shows views of the tree at different seasons over the next four years (click on any image for larger view):

2019

2020

2021

2022

It takes a long time to build a bonsai anyway, but this tree was subjected to a serious developmental delay when the decision was made to convert it from the classical styling of its earlier life to its present incarnation as a naturalistic bonsai. That decision resulted in a specimen that had been displayed for several years in the bonsai garden being made more or less unshowable for more than a decade. The restyling work might have been accomplished in less time, but the fact that the tree was unshowable meant that it didn’t get worked on as much. Out of necessity, bonsai that are showable get worked on more frequently so as to keep them ready to be shown. Trees that are in development get worked on when time allows, which usually ends up being mostly during the dormant season.

This stewartia is almost ready, I think, to go back out on display. It will be noticed that the container for this tree has changed numerous times over the years, and it changed once again in 2021. It’s now planted in a round, glazed, stoneware pot made by Charles Smith of MC2 Pottery in Tennessee. I like the look of this current tree-container combination and expect the stewartia will stay put for awhile.

Earlier this month the stewartia underwent a work session intended to set it up for spring growth. Ideally, all bonsai in the Arboretum collection get their measure of individual attention at some point during the dormant season, at which time they are cleaned, thoroughly pruned and wired as necessary. Then when spring comes the bonsai is ready for the new growing season. This is what the stewartia looked like prior to receiving its dormant season attention this year:

Here is the current appearance of this specimen:

The objective with all our bonsai is to have them improve over time. The additional objective with this particular specimen over the past ten years has been to convert it to a more naturalistic appearance. I feel satisfied with the degree of success attained on both counts. In terms of actual tree age this stewartia (at approximately thirty years) is still quite young, but it now projects the impression of a much older tree. The appearance of age is due to the practice of modeling the bonsai’s features on the example of mature trees in nature. An added benefit of the naturalistic approach used with this specimen is that the individuality of the tree is allowed to emerge, resulting in a Japanese stewartia bonsai that looks unlike any other of its kind. That sort of uniqueness is not universally appreciated, but it is a core value of the Arboretum’s bonsai collection.

The following gallery illustrates the change in structure that has been accomplished (click on any image for full view):

2011

2021

2013

2022

Just for fun, here is a comparison of the drawing made in 2014 to show the anticipated future development of the stewartia with the photo of the tree as it currently exists:

The main purpose of the drawing was to illustrate how a strongly upward projecting branch could compensate for a lack of branching on one side of the tree. I think that conceptual element played out well on the real tree, even though its upward form is not as pronounced as in the drawing. The top of the real tree developed differently than imagined, but all for the better in my view. Overall, I think the real tree ended up looking like an older version of the tree in the drawing — and that’s an outcome I can live with!

care, tree story 2Journal EntryJanuary 24, 2025year 3, winter 20251 Comment