Spring Tips

 September

 October

 November

September
In Sydney our deciduous plants should have been root-pruned by now as their leaves usually sprout in August. This month’s subject continues with the non root-pruning effect. Bonsai in essence has long passed this once impractical adage, its consequence – stunting. In the past, the description applied to bonsai was dwarfing and stunting. Both terms are the antithesis of the vibrant growth that should be associated with bonsai. The roots of a plant left to its own devices in a pot becomes compact, eventually excluding all the air. When this occurs with no vigour reserves left; the plant perishes. So sad!. It suffered enduring a short life. A healthy bonsai has the potential to pass the ‘term of its natural life’ due to periodic root-pruning. The capacity to renew young roots on an aged trunk is the elixir of life to the plant kingdom.(Aug. ’99) The best kept secret for strong healthy plant growth is the availability of a sufficient air supply.
By now the deciduous trees will have extended growth and the way one trims them depends at what stage the plant is. Young plants needing to build up their trunk girth cannot do so without growth.The shoots should be allowed to lengthen before trimming back to one or two pairs of leaves each time. This is the quicker way of thickening the trunk. Don’t worry at this point if leaves are large and internodal length is long, strength and bulk is being established.Once the tree begins to mature, allow the first leaf to open, removing the next leaf only after it becomes fully opened. The next leaf then remains, etc. etc.For the mature tree, the pinching procedure changes. The first leaf remains and then the emerging leaf is nipped out before opening, repeat as before.September in Sydney is the prime time for rootpruning Japanese Black Pines. In parts of the Southern Hemisphere August- late winter is our ‘spring’ and is the usual time for many species and although the J.B.Pine will not suffer unduly at that time a month later is better as it not only benefits the pine but also eases the workload.Very few people limit the extent of their collections and at the regrowing time much rootpruning has to be done in a limited period. To be able to space the repotting of the various species can ease the stress can ease the stress one can feel when it all begins to happen.
September in the Sydney region has seen the new leaves open with growth extending. Re- potting of most deciduous species has passed. I have mentioned before that if times for safe root pruning can be staggered it will enable a calmer approach to this very important task.In September the Pine species and in particular the black pine group prefers their roots cut back this month. The trend though, is to cut their roots in August along with the mass which is also a safe time, especially with just a few plants to work with.Although mentioning the re-potting of Black Pine (Pinus thunbergii) it also includes other members of the black pine family, possibly the most popular pines used for bonsai. The Red Pine, (Pinus densiflora). The Scots Pine, (Pinus sylvestris) and the Austrian Pine, (Pinus nigra). The Mountain Pine, (Pinus mugo) which is also a member of the black group, is not a reliable variety for use in the Sydney metropolitan area. It requires much colder winters than is experienced here, and coupled with Sydney’s high humidity becomes an unwise variety to use. The sad aspect is the short needle and amount of branches and budding that make it an ideal subject for our Art.
Calendar wise September is spring, but in the greater metropolitan region “spring” is too late for many plants. However, once again it has to be emphasised the condition of the plant shows when it is time to cut the roots. This will occur just prior to the leaf buds opening.It will be too late to root-prune the Cedrus, cedars and Abies, spruce group if the new needles have opened. However, it has not been unknown for these species to bud break as late as September.Speaking of conifers brings me to the Art Principle of Mass, which has to have a Balance with Space. Generally, the mass area of the Conifer crown in particular, is usually much too much. Artistically, mass should be lower, becoming more sparse towards the apex. Some homework? Look at pictures in books, to see how many Bonsai crowns are out of balance with the whole.Horticulturally, there is more strength in the apex. Unless it is trimmed it will weaken the lower branches.
In Sydney our deciduous plants should have been root-pruned by September as their leaves usually sprout in August. Now to continue with the non root-pruning effect. Bonsai in essence has long passed this once impractical adage, its consequence – stunting.In the past, the description applied to bonsai was dwarfing and stunting. Both terms are the antithesis of the vibrant growth that should be associated with bonsai. The roots of a plant left to its own devices in a pot becomes compact, eventually excluding all the air. When this occurs with no vigour reserves left; the plant perishes. So sad!. It suffered enduring a short life.A healthy bonsai has the potential to pass the ‘term of its natural life’ due to periodic root-pruning. The capacity to renew young roots on an aged trunk is the elixir of life to the plant kingdom. The best kept secret for strong healthy plant growth is the availability of a sufficient air supply.
October
By the October, we are into the second month of spring, but in Sydney this can change according to your particular suburb or even in some instances your street. Book learning can be misleading to the point of each providing varying advice even to the point of contradiction.Often with this misleading advice the plant dies just because you followed instructions: perhaps only your timing was wrong. Here in my area of the Sydney Hills district my plants have determined that we are indeed into the third month of the growing period whereas elsewhere the leaves may be just opening.Many factors determine the plant dormancy & re-growth sequence. As Australia & other Countries have many time zones within their boundaries so also does Greater metropolitan Sydney varying from the mountains to the sea.Most of us are aware that temperature affects re-growth but then so does light, which could be :-lengths of sunlight, the degree of light intensity as well as the duration of cloud cover. Any or all these factors will alter the dormancy & re-growth cycle. I put it this way – the plant knows the timing better than we. Let us so be guided by our plant & have nature working with us not against us.
Towards the end of October the repotting of many of the other species of Bonsai is finished and in Sydney our next direction is towards the ficus species. The warm temperate varieties require consistent nightime temperatures not falling below 12 to 15 degrees for optimum results.Results can differ if work is done prior to the above temperatures. This will depend on how drastic the pruning of roots and how much potting mix is removed. To rootprune out of season ie. when night temperatures are too cool: removing very little of the rootball is a waste of time. It is far better to wait and bare root. Figs can be treated as deciduous plants.Pruning back branches to bare wood and the shortening of thicker primary roots will not kill figs, but the setback restricts their vigour. Figs repotted at a later stage are regrowing more vigorously than those repotted earlier.The more tropical figs ie. F.macrophylla, F.benjamina sp. definitely respond to even warmer nights. Pruning during lower night temperatures can result in total or partial dieback of the branches so pruned.
Soft new growth on our bonsai in spring is an inviting target for aphids. They are accompanied by ants who ‘milk’ the aphids for their succulent sweet secretions. The spillage ‘grows’ the sooty mould, which causes the dermis (bark) and leaves to be coated by a dark furry mould.The ants and aphids must be eliminated before tackling the mould. A mild insecticide such as pyrethrum is usually sufficient. Certainly no household ant insecticide such as borax should be uses on plants.Subsequently, spraying or brushing with an old toothbrush with a mild un-scented laundry soap can eliminate the mould. Alternatively use a fungicide to treat the sooty mould.
By the calendar, we are into the second month of spring, but in Sydney this can change according to your particular suburb or even in some instances your street. Book learning can be misleading to the point of each providing varying advice even to the point of contradiction.Often with this misleading advice the plant dies just because you followed instructions: perhaps only your timing was wrong. Here in my area of the Sydney Hills district my plants have determined that we are indeed into the third month of the growing period whereas elsewhere the leaves may be just opening.Many factors determine the plant dormancy & re-growth sequence. As Australia & other Countries have many time zones within their boundaries so also does Greater metropolitan Sydney varying from the mountains to the sea.Most of us are aware that temperature affects re-growth but then so does light, which could be :-lengths of sunlight, the degree of light intensity as well as the duration of cloud cover. Any or all these factors will alter the dormancy & re-growth cycle. I put it this way – the plant knows the timing better than we. Let us so be guided by our plant & have nature working with us not against us.
November
At this time of year in the Southern Hemisphere, soft tender shoots are often accompanied with aphids and other sap sucking, rasping or chewing insects, which can cause havoc to one’s bonsai. Not only is the beauty marred but the vigour is retarded.As foliage manufactures ‘food’ (complex carbohydrates) at night for plant stamina, removal of their source of supply can weaken a plant if it is not in vibrant health. The point of this statement is the remarks of some growers, and the printed material, advising people to spray the relevant insecticide to bonsai plants at half strength.Does this mean the insects that attack bonsai are weaker than others, a special breed perhaps? NO! it is not so. Full strength insecticides do no harm to bonsai, only to the ‘bugs’. Often an oil spray used in the heat of the day may burn the leaves.The broad leaves of some Australian Native Plants (Eucalypts, Angophora and Lophostemon confertus formally Tristania) become blotched after spraying insecticides, especially pyrethrum, in sunlight although unsightly, it is not harmful to the plant.
A problem that I first became aware of was shown to me in New Zealand some years ago, and has mystified bonsai growers in some areas in Australia for some time now. I came across the solution to the affliction whilst researching a species. This particular problem occurs with the Juniperus cultivars and in particular the Juniperus procumbens Nana and possibly J. squamata Prostrata.The problem shows up on the crown only as distinct to another blight afflicting the entire plant, but that will be next months tip. This particular nasty is called Phomopsis juniperovora, which causes the crown area only; to slowly, very slowly deteriorate.Without treatment I suppose the crown will eventually and totally die. The tips become weaker & weaker and no amount of foliar feeding can improve the condition. The solution can be a problem though, because the fungicide Benlate was withdrawn from the general market following a huge lawsuit. The product has reappeared but can be sold only in 1-kilo lots at an expensive cost. Unfortunately it is the only fungicide available that will work. Now at least you know the name and what it does. If you have the problem it will cost you.
Although writing these tips for the Sydney, Australia region I am aware they are being read in sometimes vastly different climatic conditions. The timing for rootpruning in your area may differ from the time (August) that I suggest for Sydney. How to adjust your timing will depend on you plants’break of dormancy. Simply apply your timing for your deciduous Bonsai.As the nights are becoming warmer in Sydney, the time should be beneficial for working with the Ficus family. Despite variations to the climate that makes a late start for the leafbuds to burst your plants should always be the indicators of the RIGHT time for them.Often one hears of people afraid to root-prune their broadleaf evergreen bonsai, the plant is always in leaf! when then is it possible & safe to cut back the roots? Others can’t understand why their broadleaf evergreen bonsai died after cutting the roots. The reason being the plant was already in new growth which of course: is too late.Mature leaves on a plant do not indicate new growth, be aware though, with many plants it is safer to cut roots at the end rather than the beginning of dormancy.
Dorothy Koreshoff.
Bonsai Koreshoff Nursery ©

 

Japanese Bonsai