remind us where you are ...

no media is forever.. for different reasons.. as you have discovered.. i dont think you have any options ...

are you the same OP from a box question a few weeks/months ago?? .. original poster?

with all that bare lawn.. i just dont understand the need for the boxes ... except that i presume you really enjoy woodworking ... so.. all the power to ya ...

but the interface between gardening and woodworking is very problematic... as you are finding out ...

in my MI .. with ground freeze and all ... those boxes would rot out within about 3 years because of the moisture trapped in the media ...

and i think you are underestimating the root mass and size of a mature plant like this ... im not sure you could call this a tree .. definitely not a conifer.. lol ... but peeps say of trees.. the root mass can be 2 to 3 times the plant you see above ground.. just look at some of these ... and try to picture them in your wood box ...

https://duckduckgo.com/?t=ffcm&q=Chinese+Wisteria&iax=images&ia=images

no one ever learned anything.. by not trying .. so go for it ... and learn what you will .. keep us posted over the years .. so we can learn too ....

but i dont think you are going to find definitive answers in advance ...

ken

Ditto what ken said.... We have a Chinese wisteria grown as a ‘tree’ and I can’t imagine trying to keep that growing in a box without treating it like a giant bonsai and root-pruning it regularly! It might actually be worth talking to someone with bonsai experience with wisterias.... An elderly Japanese neighbour has a very attractive, very old (more than 50 years) small crabapple in their front garden. But that one is planted in the ground so, while it looks like a large bonsai, it probably doesn’t have the extent of root pruning that a bonsai would have. We try to keep our Chinese wisteria in the 8-10’ height range and it takes constant vigilance to control the growth. It’s worth a try for you to do as you plan but I think, at the very least, you need to plan on regular root pruning!

You can certainly grow wistera in a container! Many folks grow it as a bonsai specimen, so kept much smaller and with a very consdensed root system than what your box would offer. And I wouldn't worry too much about 'mature plant size', as containerized plants seldom achieve the same size they would if planted in the ground. And tree-form wisterias are always significantly smaller scaled than an unchecked vining one.

The 5-1-1 mix would be an excellent media for this purpose but it will never be a plant and forget situation. The soil will break down after a few seasons and will need to be refreshed/replaced and the vine/tree will need root pruning. Ignoring this completely will result in a gradual but inevitable decline and eventual failure.

There is also an issue with winter hardiness. Containerized plants exposed to the elements all year do have a much lower degree of cold tolerance than the same plant in the ground. If you live in a location where your soil freezes to any significant depth (more than a couple of inches), then this may not be the best choice.

Ken: I do appreciate your help. No, this is my 1st OP, though I have reached out to Al for his expertise already. I am in zone 6 (central Ohio). And as for the bare yard it is spoken for by way of a playset. As I said in the post, I really am quite set on this experiment in the manner in which I presented it: pass or fail. And while I do agree that a root mass of an in-ground Wisteria would be enormous, I am inclined to agree with gardengal. Such is the appeal of containing the runners that often accompany this plant, and I am also very comfortable with the limited growth that might result from such conditions.

Gardengal: Thanks for your insight, I have thought of lining the box with styrofoam insulation. Though since Chinese Wisteria is cold hardy much past my zone I felt as though it wouldn’t be worth the sacrafice to free air flow on all sides. When 511 breaks down, how successful do you think it might be to get in there and just break up the remaining soil and add in some fresh? I feel it just wouldn’t be worth emptying the box every time it needs new media but am certainly not opposed to refreshing top layers/regular maintenance. Also any thoughts on treating as a raised bed and leaving some access to the ground? I’m not certain how deep it can send it’s runners from.

"When 511 breaks down, how successful do you think it might be to get in there and just break up the remaining soil and add in some fresh? "

I guess you could do that :-) But the issue of root pruning will still be present and you will have to address that at some point. My medum sized containerized Japanese maples get root puned about every third year....or potted up to a larger container. The larger ones I can stretch out to maybe 5 years but by then the media is mush if much remains at all. And I can't judge wisteria root growth to JM root growth, as I've never tried wisteria in a container. Dunno if it would be faster or slower but considering how aggressive wisteria roots are in the ground, I'm guessing faster :-) I'm not sure you could stretch it out past 2-3 years without damaging or stunting the plant.

The roots of a containerized plant are the most vulnerable to cold. If the temperature drops into the low 20's, then I might wrap the box with styrofoam sheets. And bubble wrap is very effective as well.

Aw gardengal thank you very much! I’m heartened to hear about your maples. I think it wouldnt be too bad to have to get down in there about every 3 years. I wasn’t sure what an average life expectancy would be on a 511 outdoors and it just wasn’t going to be an option to repot every year. And I certainly dont have anything I could pot up into! 😂

Also when the 511 breaks down does it nearly collapse to nothing? Because it seems to me if it’s mostly air it should be much easier to remove than say compacted earth.

I was also hoping you might be able to recommend a particular type of Turface if you use that in your mix? I was thinking perhaps I need the MVP? I’m trying to price out my options as this cant prove to be too costly an experiment. Hehe.

Turface is not generally a part of the 5-1-1 mix. Just bark and a small amount of peat or coir and perlite.

Ah yes I’ve pieced that together. Not sure why I got confused, I saw it mentioned a lot in comments and thought I needed it. I’ve found some 3/8” mini mulch locally and am excited to get start. I’m thinking I might have to substitute the perlite for something like small stone though. I try to avoid perlite in large quantities for environmental reasons. Any recommendations or pitfalls to avoid in that respect? I really appreciate you answering all my questions by the way! You are so kind to help out someone with less experience!

I'm not sure I understand about any environmental concerns with perlite.....other than it is a finite quantity. But it does serve a specific purpose in the mix that cannot be met by just small stones, grit or rocks. Pumice is a reasonable alternative.

Ive heard a lot that it’s non-renewable. I cannot vouch for that though I am pretty sure it comes a very long way to Ohio. Can I ask other than the uniformity in size what it does? That way I can perhaps think of something else. I could use it if it’s absolutely necessary, but I really liked the idea of using crushed granite or something for the weight. I would hate for my Wisteria to uproot every time it storms!

The firing or "baking" process used to transform the volcanic glass into functional perlite expands the size of particle by as much as 16 times thier original volume and creates tons of little air pockets. It is like a rock popcorn! It is these air pockets that are critical in a container mix, as they assure porosity and aeration, which crushed granite or other rocks cannot do. This also assures fast drainage. Perlite is stable, retains its shape indefinitely, is of neutral pH and contains no toxic compounds. Pumice is the only other natural material that offers similar attributes.

Anything that is mined is non-renewable.........at least in any kind of time frame that makes sense to us humans :-) And that would include granite, pumice or any other kind of rock as well. And there are perlite mines throughout the western half of the US, as well as China, Turkey, Greece and several eastern European countries.

Thats great information, thank you! Ive been on such information overload from all these forums that I hadn’t investigated and had just been avoiding buying more. I will follow your advice and stick with the original formula until I learn more. I will find another way to anchor. One more question if I may... I have seen where Al says to mix prior to planting to allow reaction of the lime. Is that necessary or just recommended, and how long should I wait if so?

Okay, thank you for all the help, I‘ve been reading and rereading many of the threads and I’ve come to a decision. I hope no one feels as though their advice has fallen on deaf ears though I have decided to go with a variation of the gritty mix. An unscreened version. I’m certain someone somewhere just gasped... This may seem asinine to some, and I do understand why. I’ve read many times though where someone has said that if you understand the concept of the mixes you can adjust them to your conditions. So I’m adapting. I’m going to keep all the dust because the space so large and the plant is so young, I want the insulation and the water retention to a certain degree, and the box is only separated from the earth by the landscape fabric and probably should barely be considered container gardening anyhow I suppose. I hope the earth will wick the excess moisture to prevent perched water. If all else fails, I hope that the space is so large that by the time I need to root prune/work the mix I can change course if I‘ve gone horribly wrong. Worst case scenario I get to buy a new plant. As Ken said, no one ever learned by not trying. So I will try for the next person who comes after me. I will keep this thread updated, as I hope someone will find the information useful!