late potting or repotting your bonsai
Sneak Peek
Who doesn’t dread the idea of late potting or repotting a bonsai? It’s all supposed to get done on time. But ….
Late Potting or Repotting Your Bonsai
There’s potting time for bonsai, which is usually repotting time. It’s supposed to happen at the time which is ideal for whatever species you’re growing. Now, everyone out there who always does this at the ideal time, raise your hands ….
I committed my first potting/repotting sin over 30 years ago, and am still going strong today! No, it’s not something I do for fun, it’s just a necessity sometimes. The good news is, I’ve learned a few tricks that pretty much ensure my trees will survive my transgressions. I’ll share them with you today.
Let’s start with this small Swamp maple bonsai I first potted back in 2019. I had grown it from seed, and after a few years it had a nice trunk with good movement and taper, and I knew I could complete the development of the tree in a bonsai pot. That was two years ago, of course, and as you might suspect from the size of the pot it’s in, there isn’t any more room for roots. You can see this lack of space reflected in the foliar growth – the leaves have some deformation in them. So the tree is struggling to continue on.
The obvious answer is to repot the tree. The obvious problem is it’s already fully in leaf. What to do?
First let’s take off the ugly foliage. It’s going to have to come off anyway, as it’s much too large and the needs of ramification mean defoliation step by step as new growth emerges.
Out of the pot it comes. I think the problems with growth we already noticed directly reflect the overcrowded root system.
Now, you may be wondering if it’s okay to root-prune at this time. I can say I’ve done it, but when I do it’s usually a light root-pruning. Many species can take a lot of abuse, but there’s no point in pushing things if you don’t have to.
In this case of this tree, it needs large pot so that gives me the opportunity to slip-pot and not cut any root at all. And that’s ideal in cases like this one.
I just in some round pots from Byron Myrick, and I think this one suits the tree very nicely. Obviously it’s roomier, and that will help me achieve my goal of increasing the trunk size of this tree (yes, I know that’s a slow process but I accepted a smaller specimen when I first potted it; if I had wanted a thicker-trunked specimen I’d have put it in the ground).
It’s fun to push the envelope from time to time, so how about potting up this Ginkgo today? Well, the tree is fully in leaf so that’s going to be risky. The bonsai pot this tree goes in is going to be a lot smaller than the nursery pot you see – that means a lot of roots will end up on the ground. So my risk goes up quite a bit. But there are a couple of things you can do when faced with this situation.
First I need to pick out a pot. There’s this Kintsugi I made over the winter. The tree will certainly go in it fine, but I’m interested in a more permanent home.
Here’s another Byron pot, and I’ve got to say I think this match was made in heaven. Let’s find out.
Yes, I think this really nails the composition. With this Ginkgo, I’m not looking for a much heftier tree; I’d like it to stay the height it is now, and fill out over time. So this pot should suffice for a very long time.
Okay, so the tree’s potted now and it has lost about 75% of its root system. That’s risky, to be sure. So how do we mitigate the risk? One thing I’ve already done is to remove one of the leaders on the tree. That’s not a huge amount of the top-growth, but it is some and it helps to balance the root loss. Whenever possible, I recommend keeping the balance between root removal and foliar removal as equal as you can. That way the stress on the tree will be lessened.
I have one more trick to ensuring (as best I can) that this tree survives the late potting.
Always keep a supply of produce bags handy. They’re great for maintaining the humidity surrounding the foliage of your tree, which prevents transpiration losses while the root system regenerates. I expect to have this bag on the tree for two to four weeks.
You may have noticed the twine I used to lash the bag to the pot. In your garden or yard, anything that an act as a sail will do so – in fact, if you want to kick up a breeze try bagging some cuttings. It works for me every time!
Let me know what you think of today’s work. Do you pot or repot out of season?
Interesting read. I have re potted in the off season more than a few times. Not all were successful. Then I discovered Wilt Pruf. I’ve collected bald cypress and water elm in late august with success by using wilt pruf.
Have you ever used wilt pruf? it seals the leaf (if applied properly)to prevent moisture loss from transpiration. It lasts about 4 weeks. Just enough time for the roots to recover from re potting or collecting.
I have tried Wilt Pruf, Dennis, but it sounds like a good idea for late potting/repotting. For summer collecting, I always defoliate as a precaution – so Wilt Pruf wouldn’t be of any benefit.
Very informative for this novice. Thanks
Thank you, Jim, glad to help.
I was walking down the street near my home the other day, two years ago, and saw something out of the corner of my eye. In the rotting crook of a pear tree was a sapling. It was a small red maple about pencil thick and had a nice S curve. I carefully teased it out of its dry rotted bark home and stuffed in a plastic bag I had in my pocket with all the roots intact. This red maple is now in a 6-7″ wide pot I made and seems ok. I was rather pleased with myself for having not only saved a tree unlikely to fare well, but also scored a “pre made” bonsai and that I thought was worthwhile but anyone else might think was a weed. About 16″ tall maybe.
Training is “making it up as I go” “bend this that way, bend that this way and hope it works”.
I notice that some of your trees are fairly slim. I keep seeing this rule of 6 about trunk thickness versus height. I assume you ignore it or expect growth over time to fill out the trunk?
Danny
The 6 to 1 rule is the “classic” bonsai ratio, and gives a pleasing impression to the eye. But not all trees in nature have a 6:1 base to height ratio, nor do they need to. Think of your typical flat-top Bald cypress. I would assert that if the trunk had a 6:1 ratio it really wouldn’t look right. A bigger ratio gives a “tall tree” impression, and I have no issues with it. The key in those cases is not to let the branches get overgrown. If you do, the tree looks juvenile and that’s not what we’re after.
If I follow you, the higher ratio means more height/less girth or a “taller/skinnier” look. Also, if the branches get too thick relative to the trunk thickness it reduces the appearance of age, correct?
If that happened would you recommend ‘starting over’ by cutting the too-thick branches off at the trunk and hoping dormant buds grow in the right places to get thin branches started? Or maybe cut back the thick branches as much as possible (to a leaf or node if there is one close to trunk so the branch remains alive) to get them to taper like you do with the leader?
What if you had branches where you want them but the lowest one is visibly younger and thinner while the second or third one is older and thicker? You would ideally want them to be thinner as you look from low to high in the tree, right? If you cut them off you might not get a new set where you need them or good new branching at all. What then?
Thanks, Danny
Yes, the “taller/skinnier” look is exactly what the higher ratio produces, and frankly I love well-executed “tall tree” bonsai. You certainly don’t want your branches to get too thick relative to the trunk thickness, regardless of the design. Correcting this problem in deciduous trees is often possible by removing the branch altogether and starting over. Most species will rebud at the site of the removed branch. Cutting back older/thicker branches will usually, but not always, give you rebudding where you want. It depends on where a leaf node was originally, and for older branches it’s often not possible to tell. You do want your branches to be thicker in the lower parts of the tree than those higher up. This is usually corrected by allowing the lower/thinner branch to run, which will naturally cause it to thicken from base to tip. If your higher branches are simply too thick for the trunk thickness, then those have to be removed and begun again (and you have to take the risk of no rebudding where you’ve removed them).
Unfortunately I believe we all pot off season, I’m in the south east, it goes from 50 degrees to 90 degrees in a day, so potting out of season happens fast. I like your humidity tent idea, ever have any fungal issues under the tent?
I’ve also used a dark bag over oaks after collecting and defoliating to direct energy to the roots. Limited success with that!
I haven’t had any fungal issues when tenting, Kyle. Also, I don’t use dark materials because I want sunlight to get to the foliage (super important). Not direct sun, but sunlight.