Growing a bonsai tree from stem cuttings vs. seeds
Updated: Apr 4, 2020
Hello again and welcome back. Today, I'm going to show you how I started growing my Betula pendula 'Youngii' bonsai from stem cuttings.
Growing a bonsai is one of the many skills I wanted to learn. I have attempted growing a Japanese black pine from seeds before and I managed to get 5 seedlings from 20 seeds and 3 survived pricking off and one survived until 2 years of age and because I neglected it, it died.
That was my seedlings weeks after I took them out of the refrigerator. I have to put it in the refrigerator for 6-8 weeks to break its dormancy. In horticulture, we call this process as stratification. To support its growth, I have to put it under an artificial light as well.
I transplanted the most vigorous one and named him as well. As per the label, Nagato is already two months old. I don't know why I wrote 'due', instead of 'planted'.
Compared to other seedlings, trees grow very slowly. So, if you are thinking of growing a bonsai from seed, you should be very patient.
Here are his siblings, trying to catch up. As you can see on the picture, four seedlings are emerging and the other one is already on his own pot. In total, I got 5 seedlings from 20 seeds which means it has a low success rate. I wasn't as skilled at the time, so it can be factored in also, foreign species, like this Japanese black pine, might struggle in a different climate. This is called provenance, where seeds from other side of the world might not thrive due to environmental factors. But generally speaking, growing bonsai from seed is really time-consuming and needs a lot more maintenance.
So that was my experience with bonsai, this time I am going to try growing it using stem cuttings.
This is Betula pendula 'Youngii' or weeping birch. It is my neighbours' tree, but I cut a bit of its twig that reached over our side of the hedge using secateurs.
You make a straight cut under a node.
On this experiment, I am going to wound my cuttings to make it easier for the roots to emerge. To wound a cutting, using a sharp pocketknife, strip the woody layer of the stem to expose the green layer which is called the cambium layer. This is where our new roots will emerge.
If you have access to root growing hormone like IBA, you could dip the wounded cuttings there as well. This would make roots develop faster. But because I don't have access to one and most garden shops are closed due to covid-19 , I will just wait. Based on our cutting trials in school, semi-hardwood cuttings would approximately take 5-8 weeks before enough roots develop.
Now, we need to set up our growing media. I used a bonsai potting mix and put it on a takeaway container with 'stabbed' cracks for drainage. This growing media has seramis on it which would improve water retention so be careful not to over water your bonsai.
After filling your tray, water the soil. Stick your stem cuttings in using a dibber or a chopstick.
This is my cuttings after 4 days. The buds have emerged but, I don't expect roots yet.
Also, I kept it on top of a radiator to keep the soil moist and warm. I also covered it with white plastic. It is preferred to use clear plastic, but I don't have one.
Be careful that the temperature should not be too hot, 18 degrees would be perfect.
I will observe this for the next weeks. I don't water them as much as well, only when the soil is dry.
I will post an update about this so watch out for it. Thank you and I hope all of us would have a success story with our planting endeavours.