Harunobu's "Azalea 20-25 Contest" entry

[Forsoothe!]

What exactly are you saying? I saw your other post on shoots with seed pods sometimes not generating new shoots because they are weak. I agree that weak shoots sometimes don't grow new shoots. And having a seed pod to develop can make them relatively weaker. And that actually pruning that branch can reset this and lead to backbudding when otherwise the dormant buds are being kept dormant by the seed pod. And that once the seed pod is open/gone and the summer leaves are discarded because they are old, the branch is dead from weakness.

But that's a different debate, I think.

Obviously, for an azalea to flower in spring, it has to grow flower buds in the autumn before. But I don't get it when you say you need seed pods to mature for flower buds to mature. Many azaleas never have their flowers fertilized and never get seed pods. Hose in hose azaleas can never set seed pods. I don't have experience with azaleas that are grown too far north where the flower season is too short for them to grow properly and set flower buds. It does make sense though. The plant has to decide when to switch from spring leaves to summer leaves. And when to switch from growing summer leaves to growing a flower bud. And to decide when to go dormant. And not every shoot ends in autumn with a flower bud. And it has to decide when to spend sugars on new growth and when to save sugars as energy reserves. And how to balance new root growth with new leaf growth.

As for spring growth next year. Yes, those buds emerge from the base of the flower bud. But I don't think the absence of a flower bud means that there is no base, and that therefore they cannot emerge. In spring, the entire plant comes out of dormancy and it is trying to spend the energy reserves to push out new growth. If it can't do so from the preferred spot, it will push it out from somewhere else. Would under this theory of yours no or less spring growth happen from the buds that are just budding out? Obviously, those shoots won't develop flower buds this year.

If a flower bud is removed in spring, it could inhibit dormant buds in autumn. Removing it in spring will limit the water requirements and not block light for the leaves underneath it.

I am not happy with the amount of growth on this cutting right now. I think it would have done better if planted in full ground. I think it will be better if I plant it in the full ground right now. I think it would have done better if grown in peat with either kanuma or perlite to improve drainage. But it will stay in kanuma because I wan to know how well it does this way.

I could put it under growth lights and try to gain a competitive advantage that way. Kind of tempted to keep it inside under lights this winter. There's actually no rule against it. I am kind of curious how much of a difference that will give between this cutting, the one in the full soil, and all the other ones that would have stayed outside. But I think kanuma for a plant inside is a bad growth medium.

As for if dormant buds were always there to begin with and only start to appear when they stop being dormant, like these brand new buds. Does a shoot that grow generate a whole bunch of dormant buds and most of them stay dormant always? Or are these buds I have now created from nothing? I don't know, but I think the answer is out there.

I know that for evergreen azaleas specifically, there is some research out there on chemical pruning/decapitation of cuttings for the purpose of developing nicely branched plants. The Belgians figured out the right chemical and concentration to spray to kill only the apical tips of young plants/cuttings.

You are studying more growth aspects than my little mind can grasp, so I'll say little about kanuma, et al. I also don't know anything about the genealogy of Azalea. I speak only to what happens when a plant that is hardy in USDA zones 8 to 5 is grown in 5, sometimes. If the plant needs the zone 8 length of growing season to complete all the phases of growth including maturing seeds and then next spring's flower buds, that amount of growing days (hours) may not be available in zone 5, so the last phase, maturing flower buds may not be completed. I am saying that the seed ripening takes priority and resources normally used for maturing flower buds are used for seed ripening at the expense of flower buds.

Further, I am questioning whether or not the foliage buds that follow flowering on flowering stems are matured in autumn or spring.

 

[Harunobu]

September 15, to the shoot we have been observing; it added 3 more small leaves, as well as 3 more tiny ones. No flower buds on this plant yet. It is adding more summer leaves.


Besides that, it is now backbudding at 5 spots



This is the type of growth that extends fast and that you also see early spring. There are 3 new shoots just above the soil line. These shoots will not mature or develop flower buds this years. But they can become either main branches or sacrificial branches to increase the taper. These are very far removed from creating reverse taper. So I can grow out all three of these for at least all of next year. Probably 2021 as well. These buds are helpful, because it means I won't have to prune, and sacrifice growth rate, to get them. I am getting them for free. So the only pruning I will have to do the coming 1 to 2 years is preventing reverse taper. Since I don't want to grow a Y-shape twin trunk, I probably will have to prune back the most dominant branch. Which is the one on the right that I wired paired up with the main trunkline.

In the very first picture of the plant in the OP, the this right branch actually looks taller/more dominant. This branch and the left part of the plant look about equally strong. But because the left part has two additional sidebranches, this is the main trunk line. So as of now, I think that late winter 2021, I will prune back that branch leaving just two leaves. If it drops all spring leaves, I would have to cut into old wood to prune that branch because that branch will be bald with a whirl of summer leaves at the tip surrounding the flower bud. This cultivar likes to drop spring leaves early. If it does so, that branch I want to make less dominant will weaken automatically. In that case, I may decide not to prune in 2021 but just wait. I want it to backbud on that branch, but close to the main trunk. But I also don't want to cut back in old wood, and lose the branch entirely. In my drawing/GIF, I cut that branch back to half a cm in April 2021. And then I predict it will back bud on that half a cm. That is quite a best case scenario in that GIF.

One could remove the branch entirely and regrow new ones. But this is a 5 year competition. Not sure if I have time to have a bald trunk halfway the competition.

 

[Deep Sea Diver]

Nice, glad to see this azalea finally getting legs underneath it!
cheers
DSD sends

 

[Harunobu]

Apparently, all shoots were still considered to be too immature for flower buds (autumn 2019). And without flower buds, it is not considered a terminal bud. And no terminal bud means that there cannot be a new whirl of shoots. So a shoot goes dormant, then wakes up again, grows a little bit, and sets the flower bud. It cannot do a full season of growth in 2020, because it didn't complete 2019 yet. It has to finish what it started in 2019. And once that is done, it has to skip 2020.

This theory is better displayed by my other cutting;

Satsuki azalea 'Hekisui' - cutting to bonsai?

4 July 2020: \ 15 September 2020: Annotated plant: Wire applied to get some movement in the main trunk. I still suck at wiring, but at least I didn't snap off any buds or branches. The trunk can bend more, but for now the wire isn't heavy gauge enough to bend it more. Maybe next year in...

www.bonsainut.com

That explains why at the first node of the Hekisui cutting, there aren't new whirls. Only extensions of the existing shoots.

This one only had 2 flowers in the center shoot. And from the base of that shoot, you get several new ones. If there is no flower bud, you cannot get a whirl of new shoots. You can only extend the current shoot. So all these branches couldn't grow more than they did, because none of them met the flower bud threshold in late summer 2019.

Of course, that is different next year. But those shoots that it is backbudding now, under this new theory, they can only grow a limited amount. They don't have flower buds, so they can only extend as 1 shoot. Pretty sure these terminal ends will now grow their flower buds. It is a bit surprising that they have not done so already. But there should be 5 flower buds. And from the base of those, I should get 5 whirls of new shoots in 2021. That is my prediction. I should create a new GIF and see if it comes true.

 

[Deep Sea Diver]

Interesting. Naka et al in Satsuki Techniques of th Satsuki, recognizes the halt in growth when buds form. It is emphasized when growing seedlings out for whips from cuttings at every transplant to keep the new transplants out of direct sunlight for 2 weeks for each transplant. Stating that "If exposed to direct sun (high intensity light) during this period flower buds with form and the growth will stop. Also to remove any buds that do form to promote growth"

Also when growing out whips the authors mention, "When side branches start growing break them off downword with fingers to promote growth of a single trunk."

Cheers
DSD sends

 

[Harunobu]

If a flower bud forms on a shoot, that shoot is done growing. The only cultivars I ever saw backbud from this year's growth are the Encore azaleas, with their freaky R.oldhamii 'Fourth of July' genes.
Otherwise, the apical tip inhibits backbudding. And the flower bud has to go through winter dormancy that triggers it flowering to trigger the buds at the base.

As for tricking a plant into not developing a flower bud and to keep it elongating, I guess that can be done. But the issue this individual seemed to have had is that it couldn't finish the 2019 growth cycle in 2019. It has to end in a flower bud for it to form a new node/whirl. It cannot form a new whirl from a growth tip that didn't end in a flower bud. So it couldn't only grow a little bit, then form a flower bud. These branches should form whirls/nodes in 2021.

I think that in Naka's case, one couldn't go in and prune the tip. That would remove inhibition from that shoot, without the need to go through winter dormancy. But it would backbud sideways, not elongate more into a whip.
Of course a plant has a certain energy balance. It is still creating sugars in a shoot that ended growth by growing a flower bud. Excess sugars are either stored, or used to grow other parts of the azalea. But if you want to create a whip, you cannot prune the apical tip of your trunk line. You want that one shoot to keep growing, never ending in a flower bud. I can kind of see that a lack of light can prevent the flower bud from setting. And then it could keep extending. But what you actually want is for it to keep extending growing spring leaves. You would have more stem elongation in between the leaves. And larger leaves.

For growing whip as long and single-truncked as possible, using artificial lights to keep long days as the days get shorter in summer may do the trick. They could keep elongating, because it is still early summer in terms of daylight length. And they are not at risk of winter cold, because they are whips in a greenhouse, not plants out there to survive, like their ancestors did before them for hundreds of millions of years, in harsh nature.

Probably people think I (we) are over-analyzing stuff here. But I actually think that by taking pictures over and over of how the plant grows, and by trying to predict how it will grow, one can learn a lot. It is quite impossible to grow a plant for 3 years, then go back and try to figure out when it grew which part. And then predict how it will do so in the future. The cutting of this topic is kind of confusing to me already. I wish I had more pictures of how it looked originally. It is quite multibranched compared to my other cuttings. It doesn't have a clear node.
The Hekisui one from the other topic is very different. That one is so archetypical of how an azalea usually grows. The two nodes/whirls are crystal clear. That one is going to be more educational, I feel.