The biggest advantage of seeds is you can manage the shape of your tree from the very beginning. There are many plants that grow quickly from seed in many tropical locations.
There are no bonsai specific seeds. Growing bonsai from tree seeds can be very rewarding as it gives you full control from the earliest stage possible. It takes at least 3 years before you have a tree that you can start working on.
It is technically possible and feasible to grow sakura trees from seeds for bonsai. However, it is essential to plan to achieve success even before you choose the right seed.
The following steps may be followed in growing a Sakura bonsai tree
1. You start with appropriate treatment by stratification of seeds for proper germination by mimicking winter in order to ensure success. (Non-stratification methods too work, but it is preferable to go for stratification).
2. Rinse the seeds gently in a sieve.
3. Use gardening gloves and soak the seeds into the 10% hydrogen peroxide solution for about 10 minutes to prevent possible molding.
4. Pick up the seeds with a pair of tweezers and put them into a moist kitchen paper, then put them into a zip lock bag and then refrigerate them (not put in the freezer but in the vegetable tray).
5. Sprouting should start in 2-8 weeks, depending on the variety. Some variety takes up to months to start germination. Check for germination once a week and if necessary, moisten the kitchen paper to maintain humidity.
6. Prepare the potting mix with a slightly acidic compost for compost add about 30% of coarse sand. Ensure the seed tray/pot is sterile.
7. Transplant the sprouted seeds on to the top layers of your growing medium in your pot by about 2 cm or in seed trays coated with a copper-based fungicide to prevent molding problems.
8. Maintain a medium level of humidity by regular watering.