By Dave Allen
For bonsai you can use cultivated varieties but the wild olive Bonsai (Olea europaea sylvestris) has the advantage of very tiny leaves and short internodes.
In many cases yamadori oleasters possess beautiful natural deadwood and a lovely rough bark that indicates a high age and survival in hostile conditions. The olive is easy to care for if you can place it in a cold but frost-free greenhouse in winter.
Excerpt from Bonsai Empire
What makes an Olive a good bonsai?
They have small leaves and quick growth.
Potentially develop a show tree in 3 years.
Tips for growing an Olive as a bonsai
Find the best trunk you can as a specimen.
Then consider what style you may like to create.
What height of tree in relation to trunk?
Strip bark away from top of trunk in order to let tree dry out and facilitate successful carving through creating hollows.
In first styling you tend to have a single branch to work on.
What movement do you want to create?
Don’t cut end off that branch.
Wire it and send branch up into air in order to thicken branch.
Once it is thick enough then cut it off.
New shoots will develop on single branch.
This all takes 2-3 years.
When digging up a yamadori olive, leave fine roots around surface and cut off “onion” which is underground. Then plant immediately. New shoots will develop.
Olives will grow continuously under water for six months and still shoot new leaves. Not advocated however!! Fire survivors too.
Demonstration of tree pruning and branch selection
Starting with raw material:
Gather yamadori (material dug from the wild) or urban yamadori (dug out of urban garden).
Find the preferred front of the tree to begin with. See the tree within. If you can’t find the front of the tree, then find the back - John Naka.
If there are obtrusive branches sticking out, then shari or remove them later.
Choose main branch and cut off unnecessary branches based on alternating branch selection.
Wire in the direction that you want to bend branch. This ensures wire will not loosen. Wiring will also be neater. Undertake secondary and tertiary wiring.
Olives can be worked on mid Spring - Autumn.
Best time to dig up olives mid November - mid February.
Olives like lots of sun, good air movement, good open soil mix and plenty of food.
Olives are not drought tolerant in a pot, moreso in the ground where roots can seek water.
Fertilise early Spring - mid Autumn. Olives are happy feeders.
Heavy pruning when they are dug up. Regular pruning in Nov/Dec so there is adequate growth time after Christmas
Whichever branches you want to thicken then do not cut branch but wire into desired position and then wire remainder of branch upwards.
Clean out hairy armpits on trunk. Prune inappropriate and unnecessary branches.
Choose apex of tree.
No sealing of branches is needed when pruning. Olive seals itself very quickly in direct cuts.
Battery powered chainsaws can be very handy when trimming large overgrowths on olive trunks.
Create some deadwood carving before wiring by cutting a jin. Cut deadwood a little longer so it is easier to cut jin.
Set the branches so that no two branches are on top of each other. That will let light into tree and through branches.
When trimming branches, trim back to 2-3 leaves. Clip and grow regularly to develop floating pads.
Place developing tree into bonsai pot when it looks as though it is a bonsai, not too soon. Leave in larger pot while tree is developing.