Never did root pruning for Michelia Alba and not sure its consequences, to keep the tree from growing onto too high & big you might just prune the leaves & branches

But at certain point, wouldn’t the roots get too big for the pot?

Pot is already way too small for size of plant. The thing with growing these indoors is they are trees of some size otherwise. So some day it is just really not going to be possible to keep it going in such a confined space. In the meantime you will have to reduce the size of the top and increase the size of the container, as best you can, without spoiling the plant or making it too heavy to manage.

That’s unfortunate but I guess you can’t contain nature.

Hi @Mei, you have a beautiful and healthy Michelia alba.

I agree with Grant and Embothrium that Michelia alba may not be suitable for root pruning, because their roots are quite tender, brittle and easy to break. We have no way to know if the roots would heal properly afterward. Usually we try to avoid to disturb its root system as much as possible.

Instead, you can consider pruning the top and the side branches to control the height and encourage its side growth.

When I control the height of a Michelia alba, I will use "drop crotch pruning" method, which will preserve the shape of a tree better. (You can google the Internet for more information.)

When I control a side branch, I will cut 1/3 of its length from the tip of the branch. It will encourage the growth behind the cut.

Hope this help.

Thanks @matt2838 ! I will upsize the pot and prune the branches using the drop crotch method once it stops flowering. Hopefully that way it can stay at its current location for at least a few more years.

How will it flower if you keep it out of direct sunlight? I was wondering. You said it's flowering now. Does that mean it was not always under the covered patio?

@Meyermike(Zone 6a Ma.) it has been there since I got the tree. It gets pretty good direct afternoon sunlight. I bought it back in March of this year. It was much smaller then. Around May, it started to bloom. Not a ton but at least 40. This time around, it has a lot more flower buds, over 100.

I will be watching this thread. So far no one has come forward saying that they root pruned their plant and it survived.

But for people who are growing it in a pot, one day they will be faced with this question. There is a limit to the upsizing of the pot and pruning the tree.

Ok a quick google and I get this:

"One issue with containerized Michelia alba is that its root system will use up all the nutrient and soil space after a few years. Repotting into slightly bigger containers will work for several years, but eventually the gardener has to either plant it in ground or do a surgery called root pruning. According to Calvin, one has to time this pruning just before a new flush of leaves is coming out (usually there are three flushes of new leaves every year), take the tree out of its pot and skin off an one-inch-thick layer of roots for a quarter of the whole exposed root surface. Let the plant recuperate in half shade for a couple of weeks afterwards and maybe thin out a few top branches to balance the water needs. I have not done it myself but will probably have to try it in a few years."

So who is up to give it a try and tell us the results.

One heads up is that fleshy roots are the worst ones to deal with when root pruning.

@michaelspokane wow, Im so excited to hear from someone that does it. Do you have any additional tips on the pruning that you could share?

Please elaborate @michaelspokane

In some respects, it's like pruning branches. I prune a root back to another root, not leaving a stub. I don't take much off, perhaps 25%, and then return the tree to the same pot. I use a general purpose potting soil (not one with polymers) cut with a little cactus mix. Then I water with a solution of Root & Grow (a liquid form of the same hormone found in rooting powder). I have root pruned one of my albas once, the other twice, and the champaca once.

@michaelspokane thanks Michael! Im going to give it a go this upcoming spring :)

@michaelspokane are the roots fleshy like normal Magnolia Teddy bear (Magnolia grandiflora)? Untangling them was not easy like Lemon roots. They kept getting ripped or sheared. Next time you root prune Michelia Alba please put a video on youtube. It will help all of us a lot.

Michael thanks for that !
I always disinfect the tools I use before I cut to prevent disease!
Either way , if one grows any kind of tree in a container eventually the roots will need trimming or they will decline if not die. Tours can choke themselves off and prevent nutrient uptake.

Oh and one more thing.
Anyone who wants to trim back roots should google Bonsai methods and root trimming. There’s plenty of help on YouTube. Free courses in fact by some of the best Bonsai teachers and plant scalpers.

I found a YouTube video of a Michelia figo being crafted into a bonsai. Half way into the video, he begins to attack the roots. This treatment is typical when trees are being potted for bonsai, and I know it works (having done it before myself) but it is terrifying to watch!

How to create bonsai from magnolia plant - YouTube

My M. alba was root pruned 4 years ago after it toppled over from freak wind storm and the central branch broke. It suffered severe trauma, I had kept it in shade for over a month before it recovered, limp tiny branches and very limp leaves perked back up eventually. It was under 4’ tall after it broke and had only 3 small side branches survived that the fall. Those 3 branches quickly grew into main branches with the new central leader being at over 13’ tall right now (May 2025).

It’s been in the same pot since the last repot back in Fall 2022/Spring 2023 - forgot when. I’m not sure how many gallons but definitely much larger than 8gallons. 8gallons is too small. My pot is double hulled, a bit taller than a half barrel, maybe same width or slightly wider than a half barrel - probably 20-25 gallons. I get blooms and buds all year round and even had 3 seeds last year.

The reason it took a month for mine to recover was because I inadvertently sheared off 70% instead of 30% of its roots. I foolishly was shear happy and by time I looked down on the ground I was shocked by what I had done. It was limp and sad for a month and so was I thinking it suffered too much trauma but it bounced back. I would not recommend sheering of more than 30%.

It was in same the 12 gallon ceramic planter for a 9 years then it was repotted to 15 gallon w/o root trim. The 15 gallon single hull pot was tall so it contributed to the tree toppling over - my tree was over 9’ tall at the time but in a matter of 5 years it went from under 4’ to 13’+ tall in my large double hull pot (probably 20-25 gallons).

I’m in 10a, and I cover it with frost cloth when nighttime temps are forecasted 40° and below. It is outdoors all year round for the 15+ years I have had it. It was root pruned in October 2020 - that’s when the tree had toppled over. It took a good 3+ months before it put out new growth.

The photos taken were Jan 2021, Jan 2022, Jul 2022, Aug 2023, and Sep 2023 to give you a sense of its recovery. I didn’t think to take any pictures when I root pruned it back in Oct 2020 when its central leader broke.

As you can see, it is possible to keep a Michelia alba tree thriving in a pot for over a decade (15+ yrs) and pot upsizing, post traumas, and an accidental severe root prune.

January 2021, ~ 3 months after central leader broke and new growth emerging.

January 2022

July 2022

August 2023

September 2023

7/23/2024: bloom measures 5” across from petal tip to tip at the widest point.

July 23, 2024: one of 3 fruits/seeds that eventually made it.

November 26, 2024: seed pod opened and fell into gauze bag I had tied over it on the tree to prevent losing it.