There are several factors that come to play in the stimulating of back-budding. Light and the balance of 2 growth regulators/hormones (auxin and cytokinin) are the primary factors. I'll talk about the hormonal balance first, which is what makes the effects of pruning reliably predictable.

Auxin is produced in the apical meristems (the growing tips of branches) and to a lesser degree in leaves, and primarily the newest leaves. Cytokinin is a growth regulator produced in roots. Think of auxin and cytokinin as antagonistic toward each other - they are always fighting against each other for control over how the plant grows. Auxin suppresses lateral branching (side/horizontal branches) which forces the plant to grow longer. Cytokinin stimulates back-budding, which produces more branches and a much bushier plant. In apically dominant plants like dracaena, auxin is in control under normal conditions, largely suppressing back-budding.

Now enter the grower. By removing/pruning the apical meristems (the area at the ends of branches where growth occurs) the production of auxin is greatly diminished. This allows cytokinin to become dominant in that branch or stem, and back budding occurs. Another simple way of looking at it is, the roots are sending nutrients & water up the plant that have to go somewhere. If you remove the current growing points (apical meristems) the plant has no where to send the water/nutrients, so it quickly gets busy making NEW growing points from dormant or even newly differentiated buds.

When you wound the plant, the downward flow of auxin that suppresses back-budding is stopped at the wound site. This allows upward-moving cytokinin to be dominant immediately BELOW the wound site, the result of which is a localized area rich in the potential for development of new buds.

As for the new breaks (buds/shoots) on the stems that flopped over to the horizontal, there are two things in play. First - there is an additional photo load (more light) on the upper part of the stem, compared to when it was vertical. We KNOW that bright light stimulates back-budding, so you have that working for you. Additionally, we can look to the auxin/cytokinin antagonism for an answer. Auxin is polar. That is to say it moves downward toward the roots. In a horizontal branch, a greater portion of the auxin will be moving downward along the underside of the branch, which tends to leave an opening for cytokinin to stimulate budding along the top of the branch.

I own some river bottom hunting acreage, largely peat bog/swamp that is peat more than 20 ft deep. Tree roots grow only in the top few inches of the soil, and are frequently blown over during storms. Those trees whose roots still remain in the soil quickly develop multiple branches along the old trunk if the tree was young enough. All of the new branches emerge from the top of the leaning tree for the reasons outlined.

Different species within the same genera often have radically different growth habits, and even breaking the species down into cultivars/variants can make a significant difference in whether or not a plant tends to produce lots of basal (from the base) sprouts and remain shrubby/bushy or grow long & tall like a tree. This is still something determined by the relationship between auxin and cytokinin, with plenty of room for the grower's hand in intentional manipulations.

Al

Awesome explanation of those processes Al, Thank you very much!

A number of my dracaena's do this, branch off in different directions, sprout new shoot from the roots and curl over to the side.

Almost any I've ever seen of significant size grew like this, I figured it was normal.

Agreed, fascinating, and explains so well what my tree has done over the years. Al, I love the way you write and make such technical terms easy to understand for those of us with no formal plant education. Thanks for the time you took in writing this response and the info in it.

Dellis, you're right, I figured it was normal, too, but am glad to know more about why. Now I feel like I have some scientific info to use for some interesting experiments. These trees already look like Dr. Seuss drew them. I want to try some coils/corkscrews, maybe braiding.

I know I could google a bunch of pics, but would prefer to see pics of "y'alls" plants. Paste 'em up here and babble about them. I'm all eyes/ears.

Thank you - you guys are very kind. I find understanding how plants react to those influences that affect growth, vitality, and growth habit immensely interesting, and I love to share what I've learned so others can (hopefully) use the information to their advantage and to improve their growing skills. I know I do tend to participate mostly in the threads that require information related to physiology or the more technical aspects of horticulture - like nutrition or soil science, e.g., and it IS difficult to talk about technical subjects w/o using technical terms. I try to explain most of them, but I always hope that if I use them enough most will become familiar with their meaning, and that those who might be reading them for the first time will have enough interest to ask for clarification if they're confused or look them up. I think I'm very patient when it comes to helping anyone who is learning enabled. ;-) Plant people are generally a gentle lot, and most of my dearest friends are people I've met as a result of my own interest in plants. I think most GW members would be surprised at how active I am in the mid-MI plant and gardening community.

OK - back to the subject: Here are a few picture that very clearly illustrate the effects of grower intervention to influence growth habit.

an Aeonium arborescens
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The epithet 'arborescens' means tree-like, which should automatically tell us the plant wants to crow in tree form, which is loonng. The normal growth habit is a long stalk or two or three with a rosette of growth at the tip of the stalk and old leaves shedding on the proximal (closest to the roots) side of the rosette as the stem(s) elongate. What I did to the plant in the picture was to wait until it got good & ugly (about a foot tall, gangly looking with a single rosette at the end of the stem), then cut it back to just a couple of inches above the soil. The result was, the plant activated dormant buds at the base of old leaf scars in the immediate vicinity of the cut and produced a number of new stems and the plant you see. I then rooted the top. A very large % of succulents respond in similar fashion, so there is no reason to think you need to tolerate plants that seem to have gone beyond the 'good looking' stage.

Here are a couple of duck-foot Coleus that usually grow tall and not too bushy.
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you can see how regular pinching has turned them into something of a novelty.

I really don't have much interest in growing a plant just to watch it grow. I need to grow things I can manipulate into something interesting or unusual

A healthy little Streptocarpella growing in a nice mound form due to some selective pinching>
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4 kinds of mint, normally unruly, that are pretty tidy. I actually got these plants as cuttings from a friend in CA and grew them this way because she bet me I couldn't. ;-)
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I posted this Pilea not too long ago. I asked for a piece that had broken off a large plant this spring, and planted it in this little pot in the gritty mix.
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The plant has only 1 stem. It grew this way because I pruned it just like I would prune a shrub. It's normal habit is to shoot out a few very long branches while the remainder of the branches grow at a much slower rate.

Understanding in advance how your plants will react to pruning, pinching, and other manipulations can be a real confidence builder. You're much more apt to take the plunge if you KNOW how the plant will react and can envision how it will look in the future.

One more thing, FWIW - when you manipulate a branch of a plant that wants to grow vertical to the horizontal - as in when your Dracaena stem flops over into a horizontal or even a downward angle, it loses a LOT of growth potential and vitality. One of the tricks we use in bonsai to fatten specific branches that look out of place because they are located low on the tree but are thinner than younger branches above that branch, is to wire or train a secondary branch on that main branch to the vertical. This 'sacrifice' branch that will be removed later becomes a powerful energy sink. That is to say the plant 'sinks' a lot of energy into that branch because it is growing vertically & the tree recognizes it (chemically/hormonally) as a potential leader. This is true of all apically dominant plants, including your Dracaenas.

It would be very interesting to go to 'Google Images' for a quick look at in situ (where they naturally occur) Dracaenas. I don't think you'll find a floppy one among them, strong evidence of how important light is to strong stems. Wind also has an impact on strengthening stems as well. Flexing stimulates the production of lignan, which is what makes plants lignified or woody.

Al

Not much of a story. Grown in the same pot, in the same place for a few years, maybe five. There used to be a few more in there but I split them up and gave the others away. It's right next to my door so it gets blasted with cold all winter.

Link to a gallery of pictures.

"http://www.showmypix.com/Gal48614_Dracaena_marginata.asp"

Here's a couple of photos;
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Al, don't stop with the technical terms. I think we all know how to find their definitions when we need to and the info would be incomplete without them. You're our fill-in-the-blanks guy. A lot of people on these forums are very knowledgeable about what plants do just from experience and you give us the "why" and take the mystery out of a lot of things, especially when gut instinct is wrong.

Loved looking at your pics, especially the coleus and Streptocarpella. That little pot'o pilea is so cute! The bending/bonsai info is inspirational and enabling. Thanks for sharing pics & adding the extra info.

What are your thoughts about using the top from the branch that has sprouted a new top as a cutting for a whole new tree? I was thinking of making the cut in the spring, when everyone goes back outside. If I were to bury the naked part of the stem horizontally, would it be more likely to make multiple roots & shoots? Is there anything I can do to it to prepare for this? Has anyone else tried horizontal cuttings?

I didn't think these dracs would normally be floppy where they live outside in the ground but don't regret that mine is. I think it looks cool. That plant and I have been through a lot of moves together and it has put up with everything I've done to it so far. The plant got floppy and I've got some gray hair but wouldn't go back and change anything.

Dan, I also loved looking at your plant. It's maybe wilder than my big one and looks like it has just as much lust for life. Your link didn't work by clicking but I pasted it and was able to see your pics. What is the plastic thing? I love the way the one branch has gone way down then started to go up again. This looks like the same kind as the smaller one of mine I pictured with the new tops coming from the bottom. Was looking at it again this morning and I can't tell if they're actually coming from very low on the trunk or from the roots as I previously said. Blowing my mind how fast they are growing. If I can't tell before then, it's due to be repotted (and root pruned) in the spring. You mentioned it's been in its' location for about 5 years but do you have any idea how old it is? I know mine is at least 30 years old but, at 89, my gramma doesn't remember enough to date it farther back than that.

Here is a link that might be useful: Dan's link

I see that the quotation marks are showing in the link so I didn't write it out properly, Thanks for reposting it.

I got them from a place I used to work at that closed up in 02 or 03, They had them for a couple of years so they are at least 11 or 12 years old. Being so close to our door there isn't a whole lot of growing for close to half the year otherwise I guess they'd be bigger.

What plastic thing? The small ring shaped thing or the clear hook shaped thing?

The ring thing looks like a foam spacer from a package of blank DVDs that one of our cats probably left there, they play with things like that and leave them everywhere. I usually have pots with an anthurium and an Aglaonema set in the bigger pot so I don't see what crap falls down in there with the cats walking across it all day so as long as it isn't something that'll rot or stink or something I really could care less.

The clear thing is a borosilicate tube and rods that I melted into hooks to hold the plant more upright. But that whole plan went out the window as the plants started their loopy growth pattern.

What are your thoughts about using the top from the branch that has sprouted a new top as a cutting for a whole new tree? I was thinking of making the cut in the spring, when everyone goes back outside. If I were to bury the naked part of the stem horizontally, would it be more likely to make multiple roots & shoots? Is there anything I can do to it to prepare for this? Has anyone else tried horizontal cuttings?

Great! I think what your describing would best be achieved by taking a mallet cutting. You do this by including an inch or two of stem on either side of the new shoot, so it sort of looks like a mallet - thus the name.

While it's regularly repeated by primarily one person that repotting (as opposed to potting up) and other significant work should be done on houseplants in the spring, the idea doesn't hold up well when you consider it from the perspective of what are the most sound horticultural. Recovery from significant work and the success of cuttings are very tightly linked to how much reserve energy the plant has stored. Houseplants not grown under a quality light source (very bright fluorescents, HPS, metal halide) are usually at the lowest energy levels/reserves of the entire growth cycle. While spring before budbreak is the IDEAL time to transplant and work roots of temperate plants just about to wake from a winter's rest, houseplants have normally been struggling with unfavorable conditions in the areas of light levels, humidity, sometimes unfavorable temperatures, and in a significant fraction of plants - especially those grown in heavy soils, the effects of an increased level of solubles in the soil resultant from watering in sips. IOW, the plant will normally be weak & recovery slow.

On the other hand, waiting until Jun or Jul, except in emergency situations where it's repot or death, will find you with a plant with much more abundant energy reserves. This significantly increases the probability that a cutting will strike.

We can view rooting cuttings as a race between the fungaluglies and the plants ability to form a vascular connection between newly forming roots & the top of the plant. This needs to occur quickly or the fungaluglies win the race & clogs the plumbing with rot and your cutting fails.

I do a LOT of horizontal cuttings. Here is a picture of a future 'raft' style juniper
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another
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These were done by selecting a leggy branch & wiring it into a sinuous but flat form & pruning off branches growing downward. The more upward-growing branches were then wired upright. The whole arrangement was then covered with the gritty mix after removing a strip of bark from the entire underside of the branch (to expose cambium & improve evenness of root distribution).

You should be able to root 1-1/2" cuttings taken from healthy plants by setting them on top of 'damp' soil and pressing them into the soil so they are 50% covered. Think of log-rolling and how half of the log is submerged. If you do this in the summer, put the container in open shade & cover - maybe something like this:
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There are some VERY dwarf hemlocks (1/2" per year) rooting under the tent.

Good luck!

Al

Al, thanks for the info, very helpful, useful, and just fascinating, IMO. Very much appreciated. I've had this plant so long, waiting until summer to try the cutting doesn't seem like a long wait at all.

I was rereading what I wrote before and completely forgot to mention that both of these trees were repotted (and root pruned) this spring, April I think. I used some "potting soil" that had obviously been put in the wrong bags - it was mulch, nothing but little bits'o'wood. I was really irritated since that's not what I wanted for pots of pansies and Caladiums. But I figured that with a little composted cow manure, it would be good for these little trees, and from the results I have to conclude that it has been not just good, but great. I can't wait to see the roots when I unpot/repot again this coming spring.

Here's the new sprout I pictured before:
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BUT what's really exciting are these 3 sprouts I noticed yesterday, buried in the Philodendron that grows with this tree:
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And here is the smaller plant's 2 new shoots, growing amazingly fast! (Sorry about the stove on the front porch. It's a long story nobody wants to hear here. The bag is full of some kind of bulbs I appropriated from an abandoned house nearby. Can't wait to see what they are!)
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Purple, how many D. marginata's do you have? 20-yrs is a long time, and means more since it was given to you from your grandma.
Is the Aglao/Dieff planted in the same soil as your marginata?

Al, do you know which species Pilea you have? It's lovely. Never saw one with so much variegation.

Here are a few of my D. marginatas.

Dracaena colorama

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Dracaena, potted w/3 colors..sorry, the pic came out dark.

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Toni

Heythere, Toni! I am so in love with the plant in your top pic. What beautiful coloring! Love the Dr. Seuss look about the big 2nd one, too. Nice, thanks for sharing them!

I have 3 Dracs, the 2 from this discussion, and a corn plant that WM had on clearance this spring. I knew there was nothing wrong with it, it just wanted to get out of WM. It's grown a lot this summer, too. I think the big one making new tops out of the branches is about 35 years old. Nobody remembers when it joined the family.

Is the Aglao/Dieff planted in the same soil as your marginata? Are you asking about the Philodendron? If so, yes, those 2 plants have been companions in the same pot for around 10 years. I cut pieces of it off all the time to keep the mass at a manageable level. It's really cool the way the philo has roots about 2 feet long that grow all the way down to the dirt. This summer the philo has started making leaves 3 times as big as they used to be. I've read how they go into adult phase upon reaching the top of a tree but didn't think this little tree would be enough of a climb for it. I don't allow it to get much higher than the point where all of the branches start breaking from the main trunk, and keep weaving it around the trunks and back down to the soil. Maybe a factor as important as height is security/bracing. It's got a good grip on the tree in several places. I feel like I'm in the tropics when I look at that pot.

That philo came from my Uncle's funeral about 15 years ago, and has had a hard-knock life also. It came in a wicker basket planter with plastic liner from florist and although I knew better, I never did anything about making a drain hole or repotting it. About 5 years later, I had the basket hanging on a shady hook in the yard and the wicker broke (decomposed?) from filling up with rain water while I was away and I found the plant in a heap on the ground the next day. I discarded the roots and put several cuttings in water, gave a few away, and put one in the pot of the Drac tree hoping it would hide the soil. It started doing that right away and the cuttings in water did great and even got moved 800 miles but then got neglected and dried out. So you could say this tree saved the philo's life. At this point, I'm not sure which plant is supporting which. Like me, both of them seem to really like being transplanted to the south and drinking sweet tea.

Well, anyone actually reading my babble should get "the rest of the story" which Al was kind enough to share here.

Purple, before I forget...it's good to know taping heals a wound. Thanks.

Ha, most plants want to escape WM...lol

Sorry, mistake. I was looking at Danny's photo. Duh, lol...marginata and Aglao..

You're sooo right. Your Philo leaves ARE huge. It's said, most vine plants trained to climb upright, are much larger than if hanging. Your leaves prove it.

Wicker baskets/pots are horrible. Some look pretty, but most plants eventually rot, as the basket does.
Wicker was a big sellr in the 80's and 90's. And Expensive..my goodness.
Plants potted in these baskets are usually not compatable. Ex, succulent and Aroids.

Perhaps it's best the basket fell..don't mean to be rude, Purple.
But, look how well it's doing now.
Plus, it's sentimental. A plant you don't want to lose.

I have one plant from a funeral. Scheff arboriola. It's bushy. Because I like standard trees, I cut all but one stem, but it just won't shape. New stems/leaves grew and it's once again bushy.

Would you happen to know if vine plant leaves grow larger when attached to a plastic pole opposed to natural wood? I have Monstera friedrichsthalii. It's attached to a wavy metal pole, but leaves aren't half the size they should be. Without the pole it stand about 20'. Toni

Here are pics from this morning of the progress of the new tops:

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Toni, I was hoping someone else would answer the question about growing on plastic vs. wood. I have no idea. And you're right about how it was a good thing when that plant fell out of the wicker basket planter. It never grew much in there anyway and I like it a lot better with the tree now anyway.

An update on these trees...

The new top that is about halfway up the big branch is the one from my last pics last fall.
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Unfortunately, soon after I took those pics, this tree was blown off the porch the very day before it was scheduled to come inside. One of the long branches was badly bent and after a few months of being propped against the wall inside, it didn't seem to be healing. So I cut it off at the wound and removed all of the tops.
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You can see some of them here in other pots, along with this smaller tree whose new tops look like they will soon grow taller than the original.
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The 2 tops in the pot with nothing else were stuck in a jar of water, then put in the pot after about a month - they had formed an amazing bunch of roots in that time. I put them as sideways as I could, anticipating new tops to come from the roots. We'll see... The others were just thrust into the pots with other plants when I cut them off. None have died.

This tree has been trimmed again, a couple weeks ago, removing what was the tallest top. Amazing how fast it is growing.

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I've gathered (from various pots) the removed tops from this tree and the other one (not 'tricolor'.)

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A few of the tops are starting to make new tops.

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The other tree (not 'tricolor,') I hadn't meant to cut its' main top off but got carried away trying to bend it in a spiral with a coathanger I had stuck up through one of the holes in the bottom. Anyway, that was about 10 days ago and it was so long, I broke it in half again. You can see the top 2 pics up.

What was the middle of the trunk is here, and if what I've seen so far holds true, there's about 12 new tops about to break out of this thing.

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This is the smaller tree now, you can see the broken trunk sticking up, kinda in the back toward the bottom. No sign of a new top "bud" on that yet but since I moved the coathanger wire to what is now the tallest top and have been bending it, it may be busy just trying to cope.

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Thanks again to everyone who gave encouragement and information to help me get started. And especially to Al for convincing me to do some serious surgery on the roots. When I repotted the bigger one again this week, the roots had filled the pot again and were at the bottom, starting to circle. There were very few dead roots, and some of them had gotten HUGE. I removed all of the soil, then trimmed most back to about 8-10" and about half that long for the really big ones.

About the little Dief with the yellow leaf you can see in the last pic - that was sharing a pot with a Sans I had put in full sun. It was burning pretty badly so I pulled it out and gave it its' own pot (2 of them that used to be the same plant.) I've had this Dief for about 25-30 years, I should be nicer to it. You wouldn't believe what it's been through if I told you!

What is your take now, on the effect of root pruning - insofar as its effects on the positives - growth, vitality, ......? Any negatives you can see other than the effort itself and the fact that a plant might pout for a week or two after the work until it gets its feet back under it?

Al

I haven't noticed any pouting and if this tree could talk, I think it would say thanks. This can't be true but it seems like it's produced more growth in the past 15-16 months than in the whole time I had it before - decades. And not the spindly, weak stems it had before. The newest tops are more sturdy than those were and they're not even woody yet.

If that's not a testimonial to "get in there and fix granny's old plant" then I don't know what would be. Thanks again, AL!

For music lovers, this plant has gone from quietly humming Bee Gees "Stayin' Alive" to belting out Twisted Sister "We're Not Gonna Take It!" and occasionally some Doobies "Ooohhhhh Rockin' Down the Highway!"