Hard to see in the pic, but there are two branches that go towards the ceiling, the one that has actually hit the ceiling is the one I'm taking off. the one behind it is starved of light by the bigger one so it still have room to go before it hits.

I've also been watering it on the light side so the branch is forced to pull it's moisture through the cut which I'm hoping is making it develop roots faster?

i've air-layered my calamondin and sev. ficus lyrata: very large branches this year.
so what i did to increase the growing root mass, so as to support a very large leaf mass, was the following:
1. wait till you see many white roots thru plastic, not just one. it's a bit late in the season for best growth, but still, if you keep the plant toasty in the mid 70s it should be ok. my f.lyratas produce leaves until x-giving.
2. take a transparent pint deli container: cut vertically all the way on the side and to the middle of the bottom.then cut a hole in the bottom to accommodate your trunk+ a bit more. you'll need to bend plastic on the side vertically to create a wide opening so you can slip the container around the existing layering bag. seal it outside with postal tape and stuff some acrylic 'cotton balls' around the opening so it will not drip water so much. then stuff some more sphag or coir webbing on the perimeter to hold your soil. you can just use more LF sphag, packed well or you can add some soilless very light medium (like half perlite).
3. then you cut and carefully remove your original plastic (i use small 7oz cups instead for orig container). if you use soilless - you can put more sphag on top as mulch. and add extra medium if necessary. so now you have a good sized pot.
for your size of cutting i would actually use a quart size deli container, like yogurt. but i like transparent, so i can monitor the roots development.
4. now cover the top with cling-wrap. water slightly: keep a paper-towel around the bottom, to catch drips. and wait another 4-6 weeks.
once you see roots on sides/bottom you can cut it off.
do not water you main plant less - water as usual. also make very sure the medium in the air-layering container does not dry up.
i actually used 2 pint deli containers, top stuck inside the soil of the bottom one (top bottom cut off) - to create a kind of 'root/mix aerator', 'cause i was concerned that my soil might be soggy for the 1st sev weeks while it has no roots. you might poke a few holes mid-section. just watch the drips then while watering.
your big cane should produce buds in 4 weeks. but you can try helping it with keiki-paste that is used by orchid growers. it's bud growing hormones. i used it on my f/lyratas when i had 2 buds, but only 1 grew. the 2nd was just sitting there. it worked. it started growing too. it also helped when i chopped the main very woody trunk on f.lyrata and i was afraid it might die on me - it produced 3 growing branches and 2 more dormant buds :))).
here's the pic of my cut-off branch that i used a quart container for: to give you an idea. it's doing fine. i am growing it still in that same 1qt container and watching roots. in spring i will uppot, just before it starts growing leaves.

Here is a link that might be useful: keiki power pro that i used

How is it going, CJ?

I air-layered ficus Benjamina & a palm (don't know the name); did use plastic but there was more (I used spaghnum) - as suggested by petrushka.
Only difference was that I watered ficus with fertilizer (at every watering) - but it was done during July which is growing season (I followed advise from Al/tapla). It took less than 2 mo for roots to grow (started July 22, potted-up Sept. 3)
Palm was air layered some years before I joined GW (so I didn't have any advice) & kept inside, I probably did it 'out-of-growing-season) - both rooted very well.
In both cases I cut them off after there were more roots (actually, the roots were really nice & healthy)

Photo is of rooted & cut-off branch of Benjamina (I gave it away this spring).
Rina

I don't think it's enough to support the whole cutting

==>> perhaps that is why you should have done it on a much smaller piece ....

on some level.. you went for instant gratification as to size..

there are a multitude of ways to propagate this thing.. why did you limit yourself to this method ... you have many other branches there that you could try other ways ...

including.. at the end.. probably cutting the trunk a few inches from the media... and letting it resprout ... for sure.. there will be enough roots for that ..

good luck

ken

2 different branches air-layered:
{{gwi:99728}}

Rootball of the 2nd branch (just under 2mo):
{{gwi:99739}}

I watered thru the top:
{{gwi:106599}}

I don't have experience with corn plant, but would imagine that it should be very similar.

Rina

Just to comment on what ken suggested:

I always used to root cuttings in jar of water - but water roots are much 'weaker'. I still do it with some plants, like brugmansia and similar.
The roots grown this way are much stronger.
I know there is other ways to root, but would it work for large plant?

I agree that the 'rooting ball' should be larger.

From my limited experience, larger plant could be separated (instant gratification, right?) - see photo:

{{gwi:106600}}

Corn plant maybe roots easier?
I don't think I could have had the roots like shown another way in such a short time.
I don't have photos of the palm I did, it was as tall as CJ's plant, very skinny bare trunk. I cut it much higher (about 8" below lowest leaves). I don't know if the palm would have rooted in water?
And...I was very happy to learn something new.

Rina

There's a word for very large cuttings, truncheons. The last cutting I did of Dracaena marginata was over 3 feet long. I just cut it off and stuck it in a pot. That was about 3 months ago. It is rooted and growing new leaves. I haven't unpotted it to check the root system, but I'm sure the plant knows what to do, and that it has plenty of space to do it.

I've repotted many various species of Dracaena plants that started as cuttings, and none of them had such compact, well-branched systems as shown in your pics, Rina. But, after being pruned, potted, and checked again a year later, they do more closely resemble the roots in your pics, more smaller roots that more evenly proliferate the pot. More like what a bonsai plant would have vs. a ground-grown specimen. When confining a plant to a pot, being as far toward the bonsai end of the spectrum is good, and a worthy goal. Those roots look great!

I'm sure Dracaena is a good genus with which to learn and practice air layering, but I know it's not necessary. No doubt fun to watch, without the mystery of wondering "did my cutting root yet?" And fast results are very fun, gratifying. Once learned though, this technique can be applied to many other plants that are much more difficult to take root via cuttings. It also has the advantage of extremely high success rate. Though I don't think I've ever lost a cutting of Dracaena in particular, some very nice pieces of woody entities have been lost to failure over the years.

purple

Thank you for your input; I don't have any experience with Draceana. Vaguely remember people rooting them in water.

And as you pointed out, Once learned though, this technique can be applied to many other plants that are much more difficult to take root via cuttings. It also has the advantage of extremely high success rate.

With such large plant that OP is rooting (large piece to separate), how would you go about it? Would you just pot it up in soil?
Thnx.

Rina

Well....it's potted, for about five days now. I'm having this feeling that the roots were no where near enough to support the size of the cutting i took. The cutting I got was a bit over five feet long.....lol. It was my first time ever air laying, so If I lose it, i lose it. No biggie. I learned a lesson.

I'm half tempted to just cut the whole thing right at the base and let it re-sprout on it's own, and forget about doing the cuttings.

We'll see what happens.

IDK, Rina. I've never had a cutting that big to contemplate. It is logical though that it would do best if there are at least some roots before it's completely severed.

CJ, I'm optimistic about your cutting. But even if it doesn't make it, a new top (or 2) should start sprouting near the cut on the mama soon - at a height that will be low enough to grow for many years again.

If you do want to perform more surgery, try to wait until late spring, when recovery is easiest. And by not removing all of the foliage at one time, the mama is best able to respond with new growth.

Sending good vibes to your gorgeous plant(s)!

CJ, try to tent your plant using some large plastic sheets ? (may be taped together?) to prevent water-loss thru evaporation. you have a very large 'leaf mass' compared to root-mass. you might loose a lot of bottom leaves otherwise.
it would be even better if you could give it some bottom heat: roots grow much faster on tropicals with bottom heat. at the very least make sure to water it with very warm water and keep it in a warm corner.
you can even put it in a closed warmed up shower overnight (it's usually a very warm and humid place that tropicals just love!), just run some hot water first for a few min to make it steamy.
yes, i am serious :)!
this is truly an enormous truncheon you cut off!

Hey Petrushka...would you recommend a dry cleaner bag at this rate?

Thanks for all the tips. As far as moving this goliath around, in and out of showers, it's not gonna happen. This thing is big and heavy. I'm filing all of these great tips into my memory banks for the future. Right now, it's in the hands of the plant gods....may they be merciful.

amen ;)!
it's too big for dry-cleaners! may be 2 ripped open and taped together
? i get window film (for winterizing), it's very transparent and comes in wide sheets 4'-5' may be? 2 can be taped together for a giant enclosure.
i can see that the crown is very large and heavy.
you can avoid accidents by putting it in a 2nd heavy ceramic pot and propping it with some filler plastic bottles to stay put. or even putting it in a tall garbage basket that is propped by smth heavy, so it can't move/topple.
that's how i handle my large ficus lyrata truncheons in 4"x8" bottle-pots (super unsteady).

That shrink wrap window winterizing stuff is expensive. I'd suggest the cutting apart and taping back together of dry cleaner bags would be a far cheaper way to go about it. They are like....10 or so cents a-piece,so yeah...I'd do that! lol

I made the same mistake of cutting my very tall plant hastily and potting the parts. It dropped all leaves and looked dead. Fortunately, after 3 months of care, both the parts are developing tiny buds on their tips. Fingers crossed! I think better to be safe. Just wait.