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The European Hornbeam (Carpinus betulus) as semi-styled raw material in early 2010.
The focus of this article is the refinement, over a growing-season, of a mature European Hornbeam bonsai (Carpinus betulus) owned by a client and friend of mine. However, I had known and worked on the tree since 2009, when its owner purchased it as raw material for bonsai.
The Hornbeam bonsai in my garden in the Autumn of 2010 for pruning and wiring.
Over a number of years, I worked on the Hornbeam a series of times, wiring and styling the tree with a multi-trunk naturalistic design and planting it into a rectangular bonsai pot by Victor Harris of Erin Pottery.
Before and after styling during the Winter of 2010/2011.
The European Hornbeam after re-styling in early Spring 2015.
In early Spring 2015, the bonsai's owner asked me to prune and re-style the Hornbeam and then to keep the tree throughout the growing season of 2015 to increase its ramification. As can be seen in the above image, the design of the Hornbeam had subtly changed over the previous years and its branch structure had matured well. Individual branches had reasonable ramification, but more importantly, had developed good branch taper, an effective indicator of age in a bonsai. (For more discussion of this topic, please see Developing Deciduous Bonsai Branch Structures )
Alternative front view of the bonsai in early Spring 2015.
The hornbeam after partial defoliation during the Summer 2015.
European Hornbeam are a vigorous species and throughout the Spring of 2015 I only gave the bonsai a weak slow-release fertilizer. Fertilizing too heavily would have encouraged coarse growth with long internodes that would not be suitable for the delicate growth that the tree now required. In the relatively weak Spring sun, the tree was also given full sun, again, to encourage more delicate refined shoots and leaves.
The tree was pruned regularly throughout the Spring and new shoots were only allowed to extend a short distance before being pruned back. Again, this discouraged coarse thick growth, particularly in the vigorous areas of the tree, as well as increasing ramification.
At midsummer I partially defoliated the tree. This is a technique that I have used effectively on Beech bonsai and is described here Advanced Pruning Techniques for Eurpean Beech. A single leaf is left at the tip of each shoot as a sap-drawer, but otherwise, each branch is completely defoliated and results in a huge number of new shoots emerging from where individual leaves previously grew. Larger/over-sized leaves are cut into half to help balance the vigour of the tree as a whole.
As soon as the tree was (partially) defoliated, I ensured it was placed in the sunniest part of the garden to encourage maximum light to fall on the branches to motivate inner buds to swell, and the tree was fed very heavily with slow-release fertilizers and a weekly liquid feed. As can be seen in this article, this regime encouraged an incredible increase in branch ramification.
Note that once the new leaves emerged after defoliation, I moved the Hornbeam to a shadier part of the garden. As a species, Hornbeam in leaf are susceptible to leaf-scorch during the hottest parts of the summer and require some shading.
Detail of the partially-defoliated Hornbeam bonsai.
The Hornbeam in November 2015, after pruning and wiring.
Once the leaves had fallen at the end of the growing season in November, the improved ramification of the branch structure was revealed and could be refined. The tree was pruned where necessary, and each and every one of the new shoots was detail-wired and positioned.
Height 22"/54cm, trunkbase 7"/17cm wide.