Known as Japanese cherry or sakura, cherry blossom trees are most commonly found in East Asia, especially in Korea, China and Japan. There are many different species, such as Prunus serrulata and P. speciosa. These trees can grow anywhere between 2-10 metres tall, dwarfing other trees with their beautiful blossoms. Growing sakura bonsai from seed is something most beginners love to pursue; I did too!
When growing sakura bonsai from seed, you should note that if you are cultivating the seed yourself, then it most likely will not stay true to the cultivar of the mother stock. If this is a problem for you, then it’s best to grow sakura bonsai tree from cutting or air-layering, providing you with a tree that is true to the mother stock.
Collecting Sakura Seeds
To collect your sakura seeds, you can either collect them from the trees yourself or purchase them online from a retailer. There are many reputable sellers online that will sell mass quantities for a low price, but you should beware that seeds that are advertised as ‘bonsai seeds’ do not exist!
Any tree seed can be grown and cultivated into a bonsai as long as it has the right characteristics that are suitable for bonsai, such as small leaf size and tolerance for pruning.
Preparing the Seeds
Once you have your sakura seeds, it’s essential that you first scarify them and then put them through a stratification period. Scarification damages the outer shell of the seed, allowing it to break dormancy. Stratification is giving the seed a cold period for a period of time, mimicking winter and encouraging the seed to germinate – this will give you a higher chance of germination for many seeds.
To scarify your sakura seed, you can use something such as sandpaper to rub against the seed. Another method is hydrogen peroxide – you can soak the seed in it for around 10 minutes to scarify it. There are many different methods, and if you research them online, there are more than likely some methods that are more suited to you.
To stratify your sakura seed, you’ll need first to soak it in water for 24 hours. Any seeds that float should be removed from the batch you are planting, as these won’t likely germinate. After 24 hours, you can take the seeds out of the water. Wrap them in a damp paper towel and put something such as a plastic bag over them to retain moisture, and then place them in the fridge for around 2-8 weeks.
Sowing the Seeds
After the stratification period, you can now begin sowing the seeds! This is one of the most exciting parts, except for when they sprout. When the seeds are ready, you can take them out of the fridge and get ready to plant them.
Prepare a tray with a soil mix to sow your seeds in. I like to use a combination of compost, perlite and sharp sand for sowing seeds in, as it’s well-draining and won’t rot the seeds.
In particular, sakura bonsai prefers slightly acidic soils, so it might be worth trying to find a compost with a lower pH than any regular compost. You could use ericaceous compost.
Once you’ve prepared your soil mix, you can get to sowing the seeds. Scatter the seeds across the surface of the soil, covering them with a thin layer of the soil mix to ensure they’re covered. When this is done, you can water the mix thoroughly and leave them in a place where they get a good amount of light.
Sakura seeds may take a few weeks or months to germinate, so be patient! Once you see those green sprouts, it’ll be worth the time.
Transplanting the Seedlings
If you’ve sowed the sakura seeds densely, you’ll find that they might become a bit crowded within a few weeks or months of sprouting. When this happens, it’s best to prick them out and plant them into their own pots.
Once the sakura seedlings produce their own true leaves, you can begin pricking them out. Tease around them with something like a chopstick and gently pull them out of the soil, planting them in their own pot. Be careful with seedlings, as their roots are pretty sensitive, and they most likely won’t have many – so it’s good to try and minimize damage.
Not too sure which pot to plant it in? It would be best if you didn’t plant seedlings in a bonsai pot immediately, as this will restrict the growth of the seedling, which we don’t want. It would help if you didn’t plant it in too big a pot either, as it’ll be a lot more prone to overwatering, which can rot the seedling’s roots very quickly. Instead, aim for a smaller seedling pot.
Growing Sakura Bonsai From Seed
Within a few months, you’ll find that your sakura seedlings may have grown quite a bit. This is a very good thing for your seedlings, and hopefully, within a few years, you’ll have something worthy of calling a bonsai tree. You can speed this process up by methods such as planting it in the ground and thickening the trunk very quickly compared to keeping it in a pot.
As mentioned earlier, sakura bonsai prefer slightly acidic soil conditions compared to other species. This is relevant for other bonsai, such as azaleas. You’ll find that the species that prefer acidic soil conditions won’t do amazingly without it, and they might end up with nutrient deficiencies. When the tree gets older, you can use kanuma soil, a Japanese acidic soil most commonly used for satsuki azalea.
Unfortunately, the life span of sakura trees isn’t that long. They can range from 15-30 years; however, if you ensure it gets good and proper care, you might get a few more years out of it.
As with many other species that prefer acidic soil conditions, you’ll find that they won’t tolerate calcareous water that well, either. You can find out the pH of your water with a testing kit or by looking up your local area!
To minimize this, you can collect rainwater to water your trees with. I do this for my trees. However, this works for me as I live in a particularly rainy country.
When sakura bonsai flowers, you’ll find that their water demand will increase by quite a bit. This won’t be much of a problem for seedlings if they don’t produce flowers for a while, but for older trees, this can be a problem if you don’t address their needs. When in the growing season, make sure to give your seedlings and trees a lot more water to keep up with the water demand – they’ll be pushing out a lot more growth than in autumn and winter.
Sakura bonsai will love the application of fertilizer regularly in the growing season – whether organic or chemical fertilizer. If you’re using organic fertilizer, you can usually apply a dressing every four weeks to the surface and water it thoroughly. With a chemical fertilizer, you should apply it around every 7-10 days and adjust the concentration based on how old the plant is.
I’m not eager to fertilize my seedlings immediately; instead, I wait a few months or a year until I begin fertilizing them. I’ve found that seedlings can’t handle fertilizer as well, as this will burn their roots and kill them very quickly. If you are going to fertilize early, you should probably dilute the fertilizer quite a bit.
When your sakura bonsai gets older, you should use fertilizers high in phosphorous and potassium. This will encourage the development of flower buds, leading to masses of flowers on your sakura bonsai. However, when growing sakura bonsai from seed, you should initially use fertilizers higher in nitrogen to drive more growth out of the seedling.
Once the seedling is out of its tray and in its own pot, you can now think about when to repot bonsai seedling! I like to keep logs of when I repot my seedlings and trees, as this is helpful as to when to repot them next. With seedlings, you can best tell when they need repotting from roots coming out of the drainage holes or the roots circling themselves multiple times.
When seedlings become root-bound, this can slow down growth which is not optimal when developing a bonsai. We want the sakura seedlings to push out as much growth as possible so they can thicken and allow us to start their journey into a bonsai tree as fast as possible.
If your sakura seedling has become root-bound, it’s time to repot it! Well – it’s best to repot them in the spring. To repot your seedling, you should first loosen it out of its pot. You can use a chopstick to poke at the sides if it’s pretty stubborn.
After it’s out of the pot, you can remove a very minimal amount of soil from the root mass. Don’t work the roots too hard – as this will kill seedlings much quicker than older trees. Seedlings cannot tolerate root pruning too well, so be gentle.
Now, you can put it in a larger pot to grow and push its roots into. In about another year or two, you’ll find that it has outgrown its pot again, and you’ll have to repot it again!
With sakura bonsai, it’s best to use annealed aluminum wire compared to copper wire. Aluminum wire is much easier to work with and cheaper than copper wire, making it the ideal type of wire to use on deciduous trees and younger seedlings/cuttings.
You’ll find that if you try to use copper wire on younger seedlings, it will bite in much quicker and be much harder to work with. Copper wire is also more expensive than aluminum wire, so be careful using it when unnecessary!
Wiring your sakura seedling will help to get bends and twists in early, helping to form the tree’s structure when it’s older. Older trees with these bends and twists make beautiful bonsai specimens compared to those which don’t!
Still, looking for more detail about how to care for your seedling? You can refer to this article in which I discuss the general care of any seedling species in more detail!
In around ten years, you might find that you’ll have a beautiful sakura bonsai to show off to all of your friends! It’s lovely to see a tree you have grown from seed produce its first flowers, so make sure you’re ready to experience it!
Frequently Asked Questions (FAQ)
How long will it take to develop my sakura seedling into a bonsai tree?
Sakura trees can grow about 1-2 feet per year, so they’re pretty comparable to most other species when growing from seed. It might take around 10-20 years to develop your seedling into a bonsai tree, so you’ll have to be patient! As mentioned before, you can fast-track this process by giving it the proper care and using methods such as ground planting to thicken the trunk much quicker.
How often will I have to water my sakura seeds?
It would be best if you only watered the sakura seeds whenever the soil mix is beginning to dry out slightly. Keeping the soil mix too soggy will stop the seeds from germinating and may rot them, causing them to die completely. On the other hand, keeping the seeds too dry will also prevent germination and kill the seeds as well. It’s best to keep the soil mix moist at all times.
Do sakura trees make suitable bonsai?
Most varieties of sakura trees can be used for bonsai; they produce beautiful flowers, and you can keep them small and compact with a bit of effort. Even when the sakura tree isn’t producing flowers, they still have a stunning appearance.
Are sakura trees invasive?
Sakura tree roots can be invasive – so it’s advised not to plant them near any running water, such as your water mains. They are able to penetrate and cause damage, which could cause a pretty costly bill!