Since April 2003 I have been growing this Oak in a large pot. It's been a tough growing summer in sunny southern England. It's late summer for my large Oak and it's looking a bit untidy from all the mildew burns on the leaves. Even with careful watering I still had a lot of leaf burn on many other species - just cooked because it was too hot - no problems with nutrients or salts. About the only thing that doesn't seem to burn is the Oak. Due to the shortage of rainwater during the peak of the summer it got a lot of London tap water and this doesn't seem to have made any difference either.
This one has increased greatly in ramification this year. I've been using guy wires to keep the branches heading in more or less the right direction. I continue to shorten all the top growth and allow the lower branches to grow freely. The taper is quite nice now - and the thick side branches are enhancing the movement in the trunk.
Using the same matchbox again 12 months later you can see that the base of the trunk has expanded significantly - its approx 6cm now. And its a bit exciting to see that there may be some bark forming at the base too.
I imagine that I see some good radial surface roots forming around trunk as well.
I went to great expense (£3.95 ) and bought a soil pH checker. When I first checked the Oaks pot the pH was close to 4 - which can't be good even if the plant likes acidic conditions. I got some lime which is useful for increasing the pH and also adds calcium and magnesium to the soil. The soil is now a much friendlier 6.5 and I know that all the important macro-nutrients are in plentiful supply.
I'm find that every time I walk past it now I want to transfer it to a bonsai pot and start working on the twigs. I also know that I need to keep its roots under control and the longer it stays in this pot the more difficult it will be. Over the last 18 months it has increased in trunk diameter from 3cm to 6cm and its is tempting to let it expand another year and risk the root problems.
Its been interesting to learn that there are other bonsai growers out there going through this same process with Oaks. I hope to get to see how they have been going with their attempts.