Around every three to four years I go into this Bonsai fairly hard. I prefer doing it the same year it is due for a repot and 2011 will indeed see this one being repotted.
As you can see by the first picture the tree is fairly over-grown and if you do not remove surplus material this species has a habit of creating much inner die-back; usually only noticable when the leaves start to fall. This then has two major benefits.
1. It saves me time when I come to repot!
2. It reduces the level of growth that the new roots need to support.
3. It is so much easier to see what condition the tree is in during the leafless phase.
Structural pruning should be done along with root pruning, or before – in spring before sap starts rising as the hornbeams bleed quite profusely. It is then yet another good reason to do it now (January end 2011) All major cuts are sealed and on this tree only one small branch has been wired slightly. KHB’s do not actually respond well to wiring and I much favour the ‘clip-and-grow’ method.
During May and June much new growth will be created to achieve a new series of ramified branches. It will become essential to continually prune the tree during the late Spring (say mid May) to almost into September.
No feeding will take place for at least 6 weeks from repotting. More like 8-10 weeks. The soil medium will have plenty of nutrients included that the tree will be able to take advantage of such as trace elements and vitamins. It will be kept in a shady, wind free spot until established.
The bark is naturally a very attractive light grey colour, and during the first reasonable sunshine I will spray the entire bark to remove this current green tinge with a specialist (Bonsai safe) product.
The first shot then is the tree during August/September 2010. The second is just now in my workshop after some 5-6 hours of pruning and cleaning.