Magnolias are ubiquitous in gardens around the world. They mark the end of winter with a spectacular bloom, decorating landscapes in both vivid and subdued tones. My family home has a large magnolia that reliably graced us with beautiful blooms each year while providing a cool shaded understory during the hot summer months. They are among my favorite broadleaf deciduous species and I’m happy to be able to develop one during my apprenticeship here. Lets get to business. For starters the tree:
First to clarify, this is magnolia liliiflora known by モクレン “mokuren” here in Japan. The flowers are big, and so are the leaves. But it’s my preferred variety over smaller leafed varieties like star magnolia. Liliiflora has a smooth cream to white color bark that contrasts strongly with the large and often vibrant flowers. Despite having smaller leaves, the star magnolia has a more subdued bark and less striking flowers. Magnolias are appreciated for their winter silhouette, beautiful bark, and flowers and for those reasons I like liliiflora more. Here is a mokuren displayed during this years Kokufu. I am told by Oyakata that it’s possibly the best mokuren in Japan:
Back to the tree:
From these set of photos there are few things that are obvious. The presence of a large scar, and an overly thick branch/bulge. Since we appreciate magnolias for their bark we should aim to encourage healthy callous formation to obtain a seamless trunk. To preserve the taper and form of the tree, we need to remove thick branches/bulges but this also introduces new potentially large scars. In order to ensure good callous formation and with some advice from my senpai I decided to only make one major cut. The other branches would remain as “sacrifices” whose collective foliage mass would help heal the wounds. If I did all major cuts at once the existing amount of branches and produced foliage may not be sufficient to heal the wounds. To do so I would have to allow some of the existing fine branching run and grow thick which would introduce more imbalances to be corrected in the future.
With this in mind I decided my “major” cut should be the bulge at the back of the tree:
This would be cut, introducing a big scar. But the large branches above it as well as branches immediate to the wound would aid in callous formation. While the 2 thicker branches to the right ultimately will be removed, the wound created by cutting those branches would be smaller and easier to heal, so for the time being the bulge is prioritized.
There are some concerns with this plan. Since one of my sacrifice branches (branch number 1) is attached directly to my apex, allowing this branch to get too thick can damage the taper of the tree as well as create another future large wound site when I remove it. Because of this I want to distribute the sacrifice branch burden across multiple branches. As soon as branch 1 starts to get too thick it will be cut. Branch 2 will take over as the main sacrifice and will be allowed to run as much as possible without overly compromising the tree’s design. Conveniently there is a small back branch immediate to the wound which I expect to provide lots of callous formation. There are more branches and buds at this base to replace the back shoot when it becomes too thick as a sacrifice as well. This multi-staged plan will help me avoid creating new large wounds while preserving the taper of the tree.
A slight depression is carved into the wound so that when it heals over it is flat without a substantial bulge. If the cambium is ragged after carving, use a grafting knife to cut cleanly across the entire edge. Unfortunately the heartwood on this tree was slightly soft. I wouldn’t say rotted or punky but after debating for awhile I gave in and decided to carve out the dark wood as well. I filled it with a faux wood filler, stuff you can find at home depot for damaged furniture, voids in wood, etc. My brief experience with it is that it takes a long time to dry and harden, especially if there is any moisture content in the wood. I would not recommend it for filling large wounds, in which case cement or a hard epoxy might be more suitable. I will report back later in the growing season if it holds up.
It’s time to inspect the other wound and if the callous needs to be recut. Unfortunately I discovered that the wood at this site was not just dark but actually rotted. I carved out all the soft wood and also painted lime sulfur on the deadwood to discourage future rot or fungal formation. Lime sulfur is bad and damaging to cambium so if you have any open cuts care not to spread it there.
The tree was actually repotted prior to doing all this work, but since the repotting season turned out to be quite busy I wasn’t afforded time to bring out my camera and take nice shots. As such I’ve depicted a basic overview of how we repot some deciduous trees here and how I did this tree in particular. During my days as a hobbyist I used a fork I bent in half and take out chopsticks as my sole repotting tools. I would do things a bit differently now. After my first repotting season I’m beginning to understand how nuanced repotting can be and how important it is to properly repot trees so not only an aesthetic, but horticulturally functioning and healthy root can be formed. I hope to make some proper posts on this in the future, but for now here is a basic overview.
With the root system and scars set for the growing season ahead it was time to see if we could improve the silhouette or address structure problems.
I want to create as many fine branches as possible while minimizing clutter and the formation of bulges. On the left side of the tree there is an obvious density of branches originating from the same spot. The small lowest right branch is crossing and kind of interfering with the branches above it as well.
To begin with I removed one thick branch from this node. While the fine twigging on it added to the silhouette it was creating clutter between the other twigging and ultimately will grow to become a problem area with so many branches originating from the same spot.
Feels much better and less cluttered. My second concern was the most forward branch from that same junction. I felt that there were still too many branches from the same node and that while removing this branch would impact the trees current silhouette, branching and ramification from the branch behind it could easily fill the space.
To compensate I put on some aluminum wire and brought the branch behind it forward. The small twig at the base will develop and fill in the space behind it.
For now the work is done. The sacrifices will be allowed to run and I’ll check on callous formation over the growing season. Growth will be controlled on the smaller branches and possibly cut back to preserve the fine branching needed for the final design. Magnolias will never have super fine ramification and branching so this tree will be styled in a looser “flame” like form similar to a lot of ginkgos and stewartias. I’m excited to develop this tree and will post progress updates in the future.
11 thoughts on “Refining and repotting a magnolia (“モクレン”)”
I learned so much from this post. Thank you.
I’m glad it was useful!
The timing for this post could not have been any better. I have one growing in a pot. It is 4 ft tall now with a 7 cm base. It doesn’t have a main trunk however. There are seven 1 to 1.5 cm trunk growing out of the base. It has just finished flowering and is now lush with green leaves. Since I don’t have a place for it in my yard, I’m thinking about turning it into a bonsai. Your post provides great insight on how it should be done.
Glad it helps. Magnolia produce basal shoots easily so I’d consider removing them if they’re not apart of the future design.
Reblogged this on Wolf's Birding and Bonsai Blog.
Hi Julian, I discovered you and your website whilst searching “mokuren”. I am very impressed – thanks.
I have recently acquired two mokuren, both 5″ at base and 16″ high. They were Japanese imports to Scotland (where I live) about 2 years ago. Can you provide your thoughts of when in the season mokuren should be repotted?
I wish I had discovered your website earlier. I was at Kokufu-ten on the Bjorn Bjorholm tour back in February. It would have been good to say Hi at the Green Club.
I am looking forward to exploring your blogs further.
All the best
If you want to enjoy the flowers I would repot immediately after flowering as usually that’s when buds begin to swell. Otherwise you can cut the flower buds and wait until you see signs of bud swell. I’m not sure when this translates for Scotland’s climate but it’s best to just observe the tree to see when it begins to swell.
Many thanks Julian for prompt response.
Flowers are just over in the last week. The soil is still draining well, so I think I will keep a growth diary for 2019/20 and repot immediately after flowering next year. The trees are currently in nursery pots, so in the same timescale I will try and acquire a couple of Tokoname pots. Perhaps a chat with Shampoo? …. who I believe you must know.
All the best,
Sounds like a plan. Shampoo is a very nice guy. You definitely can find an appropriate pot from him, whoops I think I spelled your name wrong on the last reply. Autocorrect on the phone.
I’m glad you enjoy the blog. If we ever have a chance to meet in the future, please do say hi.