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Author Topic: Yuzu - Not branching  (Read 722 times)

micowave

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Yuzu - Not branching
« on: July 24, 2018, 07:35:58 PM »
Hello everyone,

I'm new to this forum and citrus plants in general.  Attached is a yuzu plant i just purchased.  It has two forks like a Y , but only one side of it is growing, straight up, is this normal?  I've read somewhere you should pinch off the top, not sure if I should do that at this point in the plants life.

I am in Vancouver, BC Canada.  I will be leaving it in a pot for a few years and probably try to introduce it into the ground with preventive overwinter.

Thanks for any info or tips.

Mike


Millet

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Re: Yuzu - Not branching
« Reply #1 on: July 24, 2018, 10:19:25 PM »
Indole-3-acetic acid (IAA) is a major auxin produce by citrus trees. IAA controls a citrus tree's growth by cell enlargement and cell division. IAA along with cytokinin (another growth hormone) controls both apical dominance and its correlative bud inhibition. In apical dominance, growth of the apical bud inhibits the growth of all the lower lateral buds (Shoots) below the apical bud by releasing the auxin IAA and sending the auxin down the shoot past all the lateral buds.. Apical dominance results from the relative amounts of IAA, which moves down the shoot to the lower lateral buds and inhibits the synthesis of cytokinins in the lateral buds, thus inhibiting  their development and branching.  Removing the source of IAA by removing the apical bud decreases the IAA concentration moving past the lateral buds, allowing cytokinin biosynthesis to proceed and lateral buds to undergo bud break and grow out into new shoots (branches) and flowers.  Cutting off the dominant apical bud removes the source of IAA and thus causes growth of the lateral buds.  Many growers cut the apical bud at approximately 30 inches +-.  Once this is done the tree should soon start to show side growth. You can read about this process further in the Citrus Production Manual.
« Last Edit: July 24, 2018, 10:23:48 PM by Millet »

micowave

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Re: Yuzu - Not branching
« Reply #2 on: July 25, 2018, 09:06:05 PM »
Thanks for the tip.  I'll trim off the top to see how it goes in the next week or so.

Walt

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Re: Yuzu - Not branching
« Reply #3 on: July 26, 2018, 11:40:34 AM »
I've never done this with citrus, but it works on most woody plants.
Cutting off the dominant apical bud does indeed work.  But another way I prefer is to make a cut above the bud you want to become a branch.  This cuts off the IAA, etc. from the apical bud and the lateral bud below the notch starts to grow.
I learned this from North Merica Fruit Explorers.  It is too slow for commercial orchards, but hobbiest with few trees find it gives more control of branch spacing.
When I used this method, not on citrus, I found it was enough to just push a razor blade into the tree past the cambium, and pull the razor blade back out.  It left no scar, good for bonsai, and it was effective.
This method works on any branch or trunk that is immature enough you can still see buds.  I find that with my shaky hands, I can't use this method on really small new growth because I end up slicing off the twig.  In my younger days I was able to do it on really tiny twigs.  When I was doing bonsai, I could get every bud to branch.  It left me with lots of options.
Note:  Millet's metod has worked on citrus and all kinds of trees for centuries.  I don't know if my method works on citrus, but I'd bet it does.
« Last Edit: July 26, 2018, 11:45:07 AM by Walt »

 

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