I find it holds up quite well. I only repot and root prune my potted trees about every five years and the media is still in good shape after that period of time. Personally, I would not mess with larger bark. It is the particle size that is important and too large will impact drainage. The perlite and pumice are almost interchangeable, provided they too are of similar size.

Depending on the size of the container (are you going with the planter or 1/2 whiskey barrels?) the period for root pruning or repotting could even be longer.

@gardengal48 (PNW Z8/9)

Oh 5 years, that good to hear! I can deal with that.

Now on to trying to find the bark! I've been having a heck of a time trying to find anything in bulk. Local HD and Lowes carry some various mulches, but reviews all say they are filled with all kinds of construction debris and non-bark materials, or they are 1-2" nuggets, or they are shredded.

Repti-bark seems like it would too expensive to fill such a large planter.

Does anyone have a source for a good bark for 5-1-1 online? Or in San Diego area?

Wait a minute,this seems to be pretty good. $75 per yard, I could fill the whole 8' x 2' x 2' planter with just over a yard. They have "bark fines" listed as 1/4" minus (composted), and also "small bark" listed as 1/4" to 1". Some of each sifted could work? Does this look like an ok product?

Just to clarify, we are looking for anything between dust and 3/8 in for the 5-1-1, right?

Yes, that's right.

In almost every case, the mix will remain structurally sound well beyond the point where good practices would dictate that the plant should be repotted due to root congestion. IOW, it won't be a structural collapse of the medium that determines appropriate intervals between repots; it will be the advancing limitations associated with root congestion.

Al