I recently picked up a field grown cork oak with some nice movement in the trunk. There are, however, few usable branches at this point.
Field grown cork oak
As I’d like to encourage new branches to grow from the trunk, I cut back the existing branches to small side shoots.
Most of the remaining branches were straight so I added a few wires.
After adding a few wires
That’s about all of the attention the upper part of the tree requires for now. The roots, however, are another matter. Because the tree was dug up from the ground two years ago, there is still some old soil in the center of the rootball. I decided to repot the tree to remove as much of the old soil as possible.
After removing old soil from the center of the rootball
It turns out that the surface roots had been buried a couple of inches below the soil. By planting the tree higher in the pot, I’m effectively making the trunk two inches longer. Here’s a close-up of the lower section of the trunk.
Close-up of the lower trunk
It also turns out there is a little reverse taper. This is common as cork oaks don’t cork up as much below the surface of the soil. By exposing the lower part of the trunk to the sun, I can expect it to begin corking and eventually overcome any reverse taper.
I repotted the oak in a clay pot that will give it plenty of room to develop new roots. Once the tree has primary branches and a healthy root system, I’ll move it into a bonsai pot.
The tree can grow freely for the next several months until May or June at which point I’ll look to cut back and wire the new shoots.
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Good Morning Jonas,
Nice looking beginning of a bonsai. Can you speak more to the use of the clay pot., it’s benefits versus others grow pots alternatives? Looks to be terra cotta. I’ve heard in the past that the Italian version (I think Italian) of terra cotta pots are fired at a higher temperature and therefore more durable or something. Or maybe a good post topic could be on grow pots and their advantages and disadvantages. Thanks for your time.
Jonas Dupuich says
Hi Kip – good question, and yes, a good idea for a future post. As trees develop, I tend to move them from plastic containers to terra cotta to training pots to show pots. I don’t know of any (bonsai-focused) research on the topic – will have to see what I can come up with!
Michael M says
I have had a couple Cork Oaks over the last few years here in Northern California. Some years I have had slow growth and am wondering if I need to change my soil mix. I have been using the 1:1:1 standard mix. I have heard of adding some kanuma to the mix or using less akadama to get a dryer soil. Or do I go to a 50% akadama mix to get a more moist soil? What do you think?
Jonas Dupuich says
Great question – am not sure I have enough experience with them to know for sure. I’ve grown them in the standard APL mix and I’ve recently tried some with kanuma. My largest tree is potted in an unusual mix with leaf mold in addition to other ingredients. To date, the trees in the APL mix have been vigorous over the past 5 years.