Sadly the new oak died. I'm more than a little angry that someone at a bonsai show would sell me a tree without roots - but it was a risk at the time and luckily didn't cost a great deal. Onto better things.
The Calamondin is also on the same feeding program and is doing very well. It also seems to want heavy feeding.
They are now on twice weekly fertiliser and once weekly super phosphate. This regime seems to be helping my ornamental quinces hold onto fruit as well.
Ive switched fertilisers to Canna tera vega. Its a product mostly used in hydroponics - but since I'm growing most of my plants in sterile soils like them i though I'd use premium nutrients. The results are very pleasing so far. I'll switch to the aqua range once this batch is finished. Go to your local hydroponics store and try some out - the other wild eyed nervous customers will be freaked out by your presence.
Its my subjective opinion - but London rainwater maybe too acidic for all plants. Phosphorus uptake at less than 6.1 seems to be much reduced.
The maple was repotted this year and had a really slow start. But with the improved PH and nutrients the roots have now completely filled the pot and new shoots are getting going.
The photo isn't very good - but i am very pleased with this tree.