I'd say not necessarily as I don't do that & my ZZ plants do just fine. I have one pot where the tuber has become exposed on top over time & it seems fine that way too.

Also, I don't recall ever reading that in any reading I've done on these plants.

My ZZ has the various tubers buried, half buried and also exposed. It doesn't seem to care either way.
I think it's just important not to bury the bottoms of the canes. If it's green, leave it above ground.

I don't get that PatchyJ, how could it stay upright if the bottom of the stem isn't buried (I assume that's what you mean by canes).

Pirate Girl, that picture demonstrates what I mean nicely!

The tubers and roots can hold the plant steady by themselves... but it's true that when I repot into loose soil I have to use a couple of rocks to hold the plant in while it gets established.
Do what works for you, that's what I reckon.

My main ZZ plant is 2 years old and is slowly diminishing.
When I got itI potted it in a 8 inch clay pot as it was too confined in its older one. I noticed this winter that the bunch of stalks was slowly looking smaller. Upon closer looking, the small stalks are all dying off. They speckle with yellow dots then turn brown and shrivle up. All of this has been happening slowly over the course of a year. The plant was in a North window, but I moved it to a west window a few weeks ago. The plant is potted in cactus mix and I am careful to neither over water or under water.
Fred

Should the plant be root bound to stay happy?

Fred, these plants do grow in some odd places in the wild (gripping onto the side of a canyon, so I heard). Plants like this often prefer to be a bit on the cramped side, but I potted mine up a few months ago and it's doing fine.
The first thing it did after the repot was to retire one of its canes (it turned yellow and then shrivelled). Then it did nothing for a while, and now it's got a new growth coming.

For lack of other places to put it, my plant is growing against a wall in a pretty poorly lit space. It never sees the sun.
I'm actually surprised it does so well there, but it does lean out from the wall to try and catch the light.

Also, not necessarily. Older, mature plants seem to be sold that way.

My 3 pots of them, 2 grown from single leaves aren't crowded & they do fine as well.

I'd try to use a pot not more than 1 or 2" bigger than the rootball, which is also some standard advice for potting succulents (which this is).

perhaps, it will be very hard to put it in a pot just 1-2" larger, but do try ;).
do not trim the fat healthy white roots - if you do it can very easily lead to root rot and then tuber rot.
very often the bottom half of the small pot will be just stuffed with healthy white roots - once you pull that mass out, it just does not fit well into anything.
i have grown the above pictured plant in the same pot for 5 years watering very sparingly perhaps once in 10 days or even less. the pot was about 7" wide and 6" high, unglazed clay inside. the plant itself was close to 3'-4' tall and wide. and growing like crazy. and would still be doing well prolly, if i did not decide that i HAD to repot it with bare-rooting, trimming of the roots and rinsing tubers.. :)...oh, well, ...i meant well, LOL. it's a goner now. i managed to save a few stalks and reroot them. you can see my posts, if you search.
there are many posts by bradley - who grows it with ease and repots without problems using apparently rather large pots.
personally, i would put it in mostly lava rocks with just a little bark and perlite. not to say, that i have done it yet. for now my left-overs are growing in coir-matting cups with pure perlite on water-wicks - so quite dry and airy with just some moisture from the bottom wicking -otherwise top 2/3 very dry.
jack, how do you grow yours? and what do you do on repot?

This post was edited by petrushka on Mon, Jun 16, 14 at 14:29

Petrushka, my plant is growing in an old ceramic cookie jar filled with coir mulch chunks and sphagnum moss (and a few pebbles to hold it down. As I mentioned, my plant leans to the side). There are no drainage holes in the jar, but the moss soaks up a lot of excess water and I only water the plant occasionally. When I do water, it's just a little bit - just enough to make the moss and coir damp.
Also, I can't really remember, but I think I put a layer of large pebbles at the bottom of the jar for drainage...??

I really don't like pruning the roots of any plants if I can avoid it. The jar I chose was about four inches wider and one inch deeper than the previous pot, so the roots fitted in okay.
I have a really odd approach to growing succulents and I'm sure it's not for everyone, but it works for me.

i just read that they are lithophytes: grow on rocks in pockets of humusy decomposed stuff. half-time very wet and hot. half-time very dry. i did try pure orchid bark and also even amts of bark/perlite/cactus mix and some lava rock too - still too wet, still rotted. the best roots that i got were between clay and thick coir matting - outside of root mass all-together. that's why i think lava rock will be very good with some coir chunks.
i also just dribble water on it - no soaking or pouring.

This is the plant I have been talking about.

My first reaction is - check for scale insects on those spotty leaves!
My second thought is that the plant looks a bit pale. Maybe it's in too much sun. ZZs don't need a lot of light. I'm actually amazed how much shade they can endure.
Thirdly, it's possible that the plant has been overwatered, a little bit, but chronically... though I'm not sure.

i can't see the tops, but judging by amt of stems - the pot is big enough, i would not repot. if anything - it's a bit large for this plant.

Yes I second that. The pot is big enough.

Same plant, If I repoted it I was concidering going a bit smaller on the pot size. Patchy Jack, what gives yout the impression that "it's possible that the plant has been overwatered, a little bit, but chronically... though I'm not sure." I read on the exoticrainforest site that underwatering is a problem as well as over watering. I have been trying to water carefully, leaving it dry a bit before rewatering. Last winter as I noticed the decline in the plant I might have stepped up the moisture slightly. Petrushka says they rot very easily and to give it only tiny amount of water. I need to do something as this plant is slowly fading away.

yep, i read exoticrainforest site too and put them in dappled sun light and when they were producing sev stalks started watering a LITTLE more. and guess what? got yellow leaves pretty soon - tubers started rotting. it prolly is like sansevieria - IF you put it in 90-95F and in partial sun it can be watered well. but that's a very big IF. if you don't have temps over 80F - don't water it more. and certainly not in winter, when most people have cooler conditions.
you def need to let it fully dry out to the bottom before you water.
look at my plant - how densely the leaves are set and how fat the bases of stalks are. too much water produces weak spindly 'soft' growth (unless you have above-mentioned hot conditions).

This is one of mine, photo from June 2013, mine are pretty young, so stems are not crowded yet (nor thickened bases either). I give mine a big drink every 10 days to 2 wks or so, 'til water comes out the bottom.

{{gwi:91223}}

Because I use fast draining mix, I can do that.

{{gwi:91224}}

Sorry, duplicate post, pls.excuse me.

This post was edited by pirate_girl on Thu, Jun 19, 14 at 21:08

interesting! so they just have 2 leaves on the stem? so how old are they?
do they produce new shoots yet? how often?
i just went and measured how much water i used to give mine. i'd just count to 11 (don't ask!) very quickly - so it turned out to be 1/2 cup - about ev week, sometimes 10 days. and that's for those huge plants. really!
they were in bark with lava stones and some soil - water would just pour out about 1/2", and then get absorbed right in quickly (most likely by the clay pot).
so what are your planted in?

Here is the transplanted ZZ. The pot to plant ratio
looks the same because the smaller branches (rachis?)
came off in the process.

Here is an update: this picture was taken May 3 2015. The plant is still not a happy camper.
Fred