You can take every wooden plant to grow a Bonsai. Nutrient requirements are the same for the big and the small plants. Either you take a scion from the cut of the Bonsai you already have or you can take one out of the garden, just from any plant you like.
Good to begin is a short scion which is slightly wooden.
Take a small pot and a light soil which is good ventilated and can carry a lot of water. Now put the scion into the soil. To push the rooting it is important not to have too much nutrient in the soil. Also the scion should not have too many leaves because these evaporate the water quite quickly.
A small indoor greenhouse – homemade or out of the shop – will help your scion to build roots. Ground heat and daylight will help as well. Water your scion frequently but watch out that you don´t drown it. If everything works well thin white roosts will be grown after round about 6 weeks.
To make a little tree out of your scion with roots you have to plant in your garden or you use a pond basket. The open design and the choice of a well ventilated soil will drive the roots towards the light, this way the roots grow quickly. The trunk will grow bigger and stronger as well, that would be same in the garden but the pond basket is better to keep more control of the trees shape. Don´t prune your little too much keep that for later and let it grow first. Replant your tree every two years and cut back round about a third of the roots at the same time. Do that consistently, so the tree remains stable and does not grow too much. Cut off the roots completely they later would be just distracting in the bonsai pot.
If your tree has the right size after a couple of years then you can plant your tree in a bonsai pot and you are allowed to call it bonsai – Bon stands for “in a pot” and sai stands for “little tree”.
If you came that far you are certainly hooked up with the bonsai culture. And you already read articles, blogs and forums. Terms like topiary, wiring and fertilizing are already familiar to you and you will get along.
Anyway we wish you all the best for you and your own bonsai.