Pruning a Cotoneaster Bonsai
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A fine choice for a first bonsai is Cotoneaster horizontatis, the rockspray cotoneaster, which often makes an interesting trunk without any training. It grows vigorously, producing many branches which take readily to pruning. New buds form on old wood. The branches of a young plant grow in a herringbone pattern, but after pruning they will send out new shoots in all directions.
- With a root hook, gently loosen the soil in the rootball and carefully disentangle the roots, working around the trunk base in a radial pattern.
- Prune longer roots, cutting away any that grow downward. Turn the shrub around, at eye level if possible, to find the best view for the front of the bonsai.
- Expose the trunk by trimming off twiggy growth. Shorten the branches, leaving an interesting structure for new foliage to grow close to the trunk.
- Repot the pruned tree in a container of appropriate size and shape. Here, a shallow oval pot balances the design of the bonsai.
The Tree in Leaf
In a few months, the bonsai’s tree like shape has filled out with new foliage, and the well-balanced design is apparent.
Clip and Grow Method
This method combines subtraction (pruning away unnecessary material) and addition (allowing new branches to grow and form the shape of the bonsai). You can use the clip and grow method to produce a more dramatic bonsai than you could achieve by pruning alone. This method emphasizes the acute angles between branches and trunk, and also encourages a rugged or aged effect.
The clip and grow method is done over two stages, and thus takes more time than simple pruning for shape. First, the original material is drastically pruned, and then allowed to regrow so that the shape of the bonsai forms during the following growing season.
Styling a Young Autumn Cherry Tree
This grafted autumn cherry was bought at a garden center. It has been grown on for two or three years after grafting to form a bushy, but narrow, plant. Instead of each branch being cut right back to the trunk at the initial clipping, small stumps or shoulders were left on the tree, because cherry trees produce new shoots which grow at a suitable downward angle from beneath such shoulders. The shoulders will be trimmed back more tidily as soon as the new shoots are strong and established. An advantage of this method is that the tree has a sturdy trunk from the start, whereas it would take many years of growing on the tree in the ground to reach this stage if the tree had been propagated from seed or a cutting.
The autumn cherry, Prunus subhirtella ‘Autumnali’s makes a splendid subject for bonsai. Most flowering cherries produce quite coarse leaves and twigs, and flower over only a short period, but the autumn cherry has fine leaves and neat twigs that grow in an elegant branching pattern. Flushes of small pink or white flowers appear in mild weather between late fall and spring.
The tree also looks impressive in the fall when the leaves turn from their summer green to shades of yellow and orange.
One Year Later
After a year, in late winter, the cherry shows a quantity of new, straight stems, extending from points where previous branches were removed. Flower buds are forming on the new growth.
Two months later, the tree is in bloom. In future seasons, it will be potted into a bonsai pot, and the branches wired to refine the shape and encourage flowering.
Pruning and Wiring
Dwarf conifers, or shrubs such as pyracantha or cotoneaster, can easily be styled into bonsai by pruning alone, but taller-growing trees often need more attention to create a well-balanced design. Usually, you will need to wire the tree, so that you can more easily control its structure and the way in which the bonsai develops.
You can grow the tree yourself to obtain suitable bonsai material, with a tapered trunk, closely spaced branches, and compact foliage. It takes a very long time but, after several years, you can prune and wire your young tree into a balanced shape with attractively positioned branches. Alternatively, you can buy one- to seven-year-old seedlings, that have been selected for bonsai, at some botanical gardens. Pot the pruned seedling into a bonsai container, and gradually refine the design over several more years.