Summer Tips




December – January
The best time to defoliate the Ficus sp, in the Southern Hemisphere is from December to mid January. Although many figs are tropical, there are varieties for the sub tropics as well as the warm temperate.The night-time temperatures are an important factor when used for bonsai. The more tropical may perform well enough in the ground in a frost-free environment, but because we prune and trim bonsai, the branch or branches may die-back if the night temperature fall below about 18 deg. This situation occurs with Ficus macrophylla the Brisbane, sub-tropical Moreton Bay Fig when grown in Sydney, the loss of a major branch can totally wreck a styled plant. The Benjamin group for instance responds well in the sub-tropics but is apt to self-defoliate in the warm Temperate Zone.The reason most people remove the leaves is to reduce their size. Defoliating them at the start of the growing season, will result with as large or larger leaves as before, and is a waste of the plant energy.

Another little realised use for the removal of fig leaves is for refinement purpose. A refined ficus is one with uniform leaf size. The leaves are totally removed at the end of December, allowing enough time for regeneration before slowing down towards autumn.

In growing back their size will be similar. As the ensuing tip bud enlarges it is, in fact several leaves furled around each other. By twisting this shoot between the thumb and index finger, and removing about two leaves is slowing the growth. It is also shortening the internodal length and thus continuing the refinements procedure. The now, tiny exposed leaf becomes premature, for it would have opened out in about two weeks, will thus be more in uniform with the rest.

This information should only be used when the bonsai is well structured. That means the trunk appears think for the height and the branch ramification is adequate. Unless the above criteria are already present, in the long run, you will not be doing justice to the plant.

Looking back over the spring growing period, I feel it appropriate to explain ‘pruning’ terminology, as often one may become confused about the purpose intended. eg. pruning is not cutting the twiggy ends.PRUNING – Severing thicker twigs, branches or trunks. This is accomplished by using a saw, secateurs, loppers, as a stub should be left for a few months to dry before using an angled bonsai cutter to gouge away a depression. Heavy pruning sometimes means cutting back to bare wood. This usually applies to deciduous species before new growth commences otherwise the region may die back to a foliaged section. If unsure it’s safer to go back to foliage.TRIMMING – The cutting away of thin/ fine twigs and branchlets. This is more efficiently accomplished with long, pointed scissors, or tiny angled cutters. The purpose is to shorten the internodes and cause division of the twiglets,

DEFOLIATION – This means the complete removal of foliage. This is usually applied to leafy plants. The main purpose is to reduce the leaf size after the spring growth has matured. In the Southern Hemisphere this can be December to mid January but before the autumn growth appears, which the latitude will determine. It is most unwise to apply complete defoliation on conifers, as foliage does not necessarily return. The leaves of broadleaf plants and Australian Natives can be removed prior to end of dormancy, advantage being fresh and unblemished foliage. The leaf stalk can be retained for further photosynthesis to take place. Use fine pointed scissors or rebound cutters for best results.

LEAF TRIMMING. – Is the progressive removal of the larger leaves that are then replaced by a smaller crop. Some foliage can come away by pulling the leaf forward without removing the dormant base bud. The point though is not to pull the leaf back toward the trunk. The resultant damage removes the replacement leaf when the bud is removed. The skinning of the skin can also cause ringbarking.

The continuing development details of English Holly dug from the ground after approx. 12 years, plus 3 prior years grown in a nursery pot had suckered & some selected for inclusion for ‘style’ when transferred to bonsai containers for transitory appreciation. (I like to develop plants to a style to suit the container)By this time the ‘Spring’ growth was allowed to grow-out until the following late Winter when again cut-back quite short. This procedure continued until the late ‘80’s.A Summer semi dormancy occurs in December in Sydney prior to re-growth about the middle of January. The ‘Spring’ shoots that were shortened back to a point past the previous cut a few weeks ago, by now are starting to re-shoot. This growth goes once again through winter where the cycle continues.
Most bonsai information advises two safe periods in which the roots of plants are able to regenerate after being shortened. These times are listed as spring and autumn (fall).  To the uninitiated this can be very misleading, resulting unfortunately with the death of their future bonsai.Some locations experience two growing seasons where summer dormancy is indicated by mature terminal leaves.  At the end of this semi dormancy, terminal buds begin to enlarge but before the new leaf unfurls.  This is the better way to explain the correct time for root-pruning rather than using seasonable terminology.Within the Sydney region on roughly latitude 33 deg. S. the correct timing for pruning the roots of many plants is late summer & late winter repotting.  This can still mislead as we have three varying degrees of temperatures in the greater metropolitan area, enough to make it slightly unsafe for some if we all repot on a given date.

Many people sill repot in autumn ie. April, May. but may run into difficulty if the temps. fall dramatically before the roots have time to regenerate. As well we have some species that prefer to be root-pruned at the height of summer where they require continuing high temperatures to enable stress-free regeneration.

The weather in Sydney has been unpredictable lately, making it difficult to know whether it will be safe to proceed with late summer root pruning. The determining factor for success is the guarantee of temp. stability.

Regeneration will still take place where a slight increase in the spring and slight decrease in the autumn night temperatures for several weeks after  The object of this tip is to allow your plant to inform you when it is ready for its ‘little operation’.

The bonsai guidelines were created in order to help enthusiasts to be able to style their plants to obtain an artistic arrangement of the plant’s structure.This can be most helpful for those who are not naturally artistic. Some aspiring artists labour at styling; not knowing which way to go and getting nowhere. Conversely, others not knowing the guidelines create very creditable bonsai.These people have a natural instinct for the beauty of line, the balance of space and mass, stability and direction. Some of the best landscape artists are self-taught, balancing mass and space effectively.

Being an Art-form Bonsai should be developed using the Principles of Art. The above pointers and more are applicable to bonsai, and should be taken into consideration when styling. Details and explanations can be found in the Principals of Art section of this website.

Dorothy Koreshoff.
Bonsai Koreshoff Nursery ©


Japanese Bonsai