Autumn starts 20 March in SA, which is only 5 weeks away! There are always so many doubts on how to prepare your bonsais for the impending arrival of the winter cold. The passing seasons are a wonderful sight to see on our bonsais, and autumn is particularly charming.
What happens to our bonsais in Autumn?
Sunrise is later, and the temperatures will start dropping, of course, this last Summer has been somewhat unusual with temperatures and all the rain, but we do expect that the autumn temperature drop will kick in. (Just a side note - research showed that March has the least amount of sunshine in the year!). In spring and summer, our bonsais have grew healthy as we have been fertilising throughout this period. When the temperatures increased, our bonsais stopped growing in order to accumulate energy, and this will continue through autumn. This energy store is need to survive the winter.
Your bonsai has collected food from the sun and transformed and treated to produce sugars and carbohydrates necessary to sustain itself. Trees breakdown chlorophyll into different elements and store them with the sugars in the roots and the trunk. Any reserves will be used in the spring.
it is at the point that the chlorophyll decomposing that the leaves change colour, loosing their green, and changing to red, orange or yellow. Once the substances of the leaves is returned to the trunk, the tree creates a layer, closing the union of the branches and the leaves, this is when the leaves fall off. Not all trees loose their leaves, evergreen trees employ other methods to prepare for winter. Conifers use their resin as an antifreeze, covering their leaves with a wax like substance and forming a “hard skin” and deep stomata (stomata is a pore found in the epidermis of the leaves). By having this cover, the tree avoids loosing water, and protection against the winter elements.
What to do for your bonsais?
there is little growth during autumn and this is the time to do some work that will sudstaintailly improve our bonsais. This is a good time to detail wiring, clean dead wood, and if necessary, transplant. If you wanted to redesign your bonsai, this would be a good time. Continue to fertilising during this time, low nitrogen, high potassium and phosphorus. This formula will stimulate strong growth, strengthen the root system and asssist in the osmo-regulation process, give greater resistance to water and thermal stress, and thereby prepare our bonsais to face the low temperatures of winter that are approaching.
This is a wonderful time to enjoy the seasonal change, and enjoy your bonsais!