Repotting is based on size of tree vs size of pot. Picture please.

Steve

How is the soil mix? Likely broken down by now, I'm lucky to get a year or two

I used the 5-1-1 mix. The surface of the media is still fresh fir bark, no signs of decomposing. A little more decomposed going deeper but still plenty of chunks of bark fines can be felt. Not to mention it dries up extremely fast. I will take a pic tomorrow when I go see my trees but they are about 4-4.5 ft tall and container I believe is 12 in diameter.

The 5-1-1 soil mix will hold up better and longer than commercial bagged mixes. This is what I use with all my containerized Japanese maples. But its longevity is also limited. 3 years is about the max I can expect from it before needing replacement.

Anything planted in a peat based soil mix is usually repotted the folowing summer.

Everything planted in the porous mixes I use in which the soil structure holds up usually after a couple of years.

Anything in which the roots have almost filled the pot, usually that summer

Anything in which I know the pot is too small and in which the roots have taken over the mix when ever I like.

I too use the 5.1.1 mix The one in which I used the 'fresh fir bark' like Repti-bark breaks down a lot slower than the one in which I use the 'composted bark'.. Same as Gardengal with longetivity with my roses.

Ok well it’s kind of too late now in the season so I’m thinking of repotting this fall before I bring it indoors. Should I root prune and pot it back up in the same pot or just stick in a bigger pot? If I have to keep repotting into bigger pots every 3-4 years, I’m going to eventually need like a 48 in wide pot for it which there is no way I can deal with when I become 80+ years old...

You can do it in the fall with a pot 2-3 inches bigger across and 2-3 inches deeper.

Steve

Or you can root prune every time you repot/refresh the soil to keep both the size of the plant and its container manageable.

Took this pic today. Diameter was 15 in and pot was 12 in deep.

The best way to tell if a plant needs repotting is to lift it from the pot to see if the root/soil mass comes out intact. This one obviously did,

and the second step in the repotting process has been taken. The first step is to prepare the new container (it there's to be one) and assemble everything you'll need for the process - tools, soil, drain hole covers, a wick if you're using one, and a water source.

While this root/soil mass is intact, roots are not badly congested, but, they will be by the time the next good opportunity to repot rolls around, so call it a toss up. I have so many trees, I'd likely let it go another year, but there's a tax to be paid in the form of lost (and irrecoverable) potential that increases as root congestion increases. Potting up and snipping roots around the edges of the root mass can partially reduce the loss of potential, but will never even come close to the rejuvenating effect of a full repot, which includes correcting root congestion in the center of the root mass and pruning large roots that ser4ve no purpose other than to take up room that would otherwise be filled with the fine roots that do all the plant's heavy lifting.

This^^^, is a healthy root system. The only large roots are directly connected to the base of the trunk to serve as plumbing conduits.

Al

I repot mine every year around Memorial Day. They aren't dangerously pot-bound at this point, but far enough along that letting them go another year would probably result in lost potential. But I keep mine in pots that are on the small side because I don't want them growing too large, so keep that in mind.

Hi, James. You might keep in mind that small pots don't limit growth unless the plant in that pot is root-bound. So, by repotting annually, you're giving the tree the opportunity to realize as much of its growth potential as possible (within the limits of other cultural influences, of course), It might be serendipity, but your course is a good one.

Many people have the misconception that bonsai are starved of water and nutrients, and kept horribly rootbound in tiny little pots in order to stunt their growth. I've even been accused of and belittled for being a tree torturer. Those ideas couldn't be further from reality. The aim of bonsai practitioners is first to reduce the amount of stress on trees to as close to 0 as possible. That means we try to optimize every cultural influence to the greatest degree possible. We then apply judicious pruning techniques that ensure the tree stays in scale to the greatest degree possible. You absolutely can rob a tree of all of more of it's growth potential, but given the stress level that levies on the plant, you would be putting its viability in a tenuous state; so, keep on doing what you're doing and sharpen your pruning skills.

Al