Bonsai Care Calendar

THINGS TO DO IN AUGUST –  By Carole Waller

August is the last month of winter and in warmer areas trees are already budding up. So it is the start of the busiest time of the year. Well-organized people will already have cleaned down their benches, prepared their soil, collected moss and pebbles etc. (If you are not well organized, like me, you will still be doing this!)


The Gold Coast Tweed Bonsai Club is one of the only clubs in Australia where members come from two states. Several members come from further South than Murwillimbah and others live as far North as Oxenford. As well as that we have the extremities like Mt. Tamborine and the Gold Coast foreshore. Within these areas we experience huge differences in temperatures, so as you are reading this information remember that I am writing it from the foothills of Springbrook, where our temperatures are more like those recorded in Ipswich than the ones one the Gold Coast Seaway.

A fool proof guide is to stop root pruning when the overnight temperatures in your area

drop below 10 degrees. Then re-commence when overnight temperatures rise and are consistently above 10 degrees. Having said that, let your bonsai, or the trees in your area tell you when to repot many species. Look at the deciduous trees growing in nature and when their buds start to swell you know the days are lengthening and the trees are waking up for Spring.

Almost every variety of bonsai can be re-potted during August, so prepare to be busy. I try to start off with a system as the Chinese Elms, Celtis, Crab Apples, Flowering Cherries and Quince start to bud up first followed by the rest of my deciduous trees such as Trident Maples, Japanese Maples and Liquidambar. I then move on to Pines, Junipers and Azaleas. I leave my figs and Bougainvilleas until the weather warms up as they love the heat.

I will admit that I have rootpruned almost every variety of tree outside the recommended seasons with success, however I apply the following theories: a) If it has soft new growth I wait until it hardens off. b) If it is a heat loving plant and I did it in winter I will protect it from the cold and place it in a warm area. c) If it is a cool climate plant and I do it in hot weather I protect it from the hot sun.

The optimum time to repot a deciduous bonsai is when the buds swell but have not opened. At this time their roots can be cut back really hard. If you are changing your soil mix you can also hose out all the old soil from your deciduous bonsai. After repotting they should be placed in a warm spot where they will be sheltered from wind, and keep a close eye on them for caterpillars and the like as their gorgeous new foliage is tender and juicy!!!

Azaleas can be root pruned during flowering or immediately after which usually works out to be July/August in my area.

Japanese Black & Red Pines and Radiata can all be rootpruned during July/August but NEVER bare root them. For the benefit of our “Beginners” I will explain what is meant by bare root. When I first came across this terminology in the 70s I thought it meant “don’t cut all the roots off the tree”, and I thought it was a ridiculous thing to say as I would never do that!!! However it actually means don’t take all the soil off the roots. If all the soil is removed from pines and junipers it could kill them as they have a fungus which grows around their roots and in their soil. This fungus is called Mycorrhiza and it is integral to the health of the tree. It is even recommended when rootpruning pines, that we place some of the old mycorrhiza into the new soil near the roots to help it spread into the new soil more quickly.

If you have to go away or are otherwise busy and missed the optimum time for repotting any of your bonsai, remember early Spring is the best time but NOT the only time trees can be repotted.

If you missed repotting your deciduous trees wait until the foliage hardens off and then do them. Just don’t take quite as much off the rootsystem. Many deciduous trees can also be rootpruned in the middle of summer but if they are done then they should be defoliated at the same time.

Pines can be repotted from July through to October and again in early Autumn which is March and April, but regardless of whenever you do them remember what I said above and don’t bareroot them.

WIRING: It is okay to wire anything that needs it just take care not to snap brittle new branches, expecially on azaleas and bougainvillea.

FERTILISING: It is time to commence feeding your bonsai again ready for the long growing season ahead. I always used Osmocote Plus as it was quick and convenient and it is still an option, however if you have trouble snapping branches on pines and junipers Boon Manakitivipart (who was the International Demonstrator at the Bonsai Convention in Melbourne in May) says that Osmocote makes branches brittle and they break when wiring. I will probably still use it and just take more care.

I also used Dynamic Lifter and again Boon said he never uses it as it becomes acidic in the soil mix over time. I used to sprinkle it on top of the soil but it goes a bit slimey. I love the product because it has a very fast effect on under-nourished bonsai and so I decided I would still use it. I used old stockings and filled them with Dynamic Lifter knotting them every few inches like a string of sausages then cut them into “sausages” and laid them on the top of the soil. An easier option is to soak some Dynamic Lifter pellets in a bucket of water for a couple of days and then use it as a liquid fertilizer. It could also be used in the little commercial fertiliser baskets that can be purchased from some bonsai nurseries or orchid suppliers. One of the most popular fertilisers around at present seems to be Seasol and its partner “Powerfeed.” I use Seasol in winter as it has no nitrogen in it but it does have phosphorus and potassium*. In winter when growth has slowed down we don’t require as much nitrogen as it promotes leaf growth. In early August which is the beginning of the growing season I change to Powerfeed as it has all the nutrients to promote fast healthy growth. *Phosphorus and Potassium not only promote healthy strong trunk and roots but also helps provide a good crop of fruit and flowers.

PESTS & DISEASES: Pine Mealy bug can start to appear around the base of candles and if not treated early can become an awful problem. It is still not too late to spray them with Lime Sulphur

Using 20mls to a litre of water, but never use it during the heat of the day or in late spring or summer when the temperatures rise above 30c. Folimat 50 is also effective on Pine Mealy Bug as well as a wide variety of other insects.

Hope this helps with your repotting but remember my advice from last month, “Don’t change what you already do if your trees are healthy and growing fast.”



We have been taught that late winter/early spring is the optimum time for root-pruning and re-potting our bonsai, and by the calendar spring officially starts on the 1st September.  However the temperature differs massively across this wide brown land of ours.  It would be inconceivable to think that in Tasmania they start re-potting on the same day as they do in Cairns! The best way to recognise when it is time to re-pot in your area is when the new buds have swollen but before they open.  If you are a ‘beginner’ and it is difficult with some trees for you to be sure then the next safest thing is to follow the seasons and start re-potting by the calendar which of course is the beginning of spring.

Almost every variety of tree is safe to re-pot during August/September/October.  If you are away in early spring and you come back and find that your deciduous trees have come into leaf, don’t attempt to root-prune them for about six weeks, give them time for the leaves to mature and harden off.  Much of what happens on top of the tree is reflected by the roots, and if you root-prune when the buds are swollen and not open, the roots will be waking up but not really growing so cutting at that time doesn’t harm them but if you cut them when the leaves have only been opened about a week, then the roots also have only been growing about a week are not very strong and cutting at this time could cause a major set back, if not ‘death’.  When the leaves on the tree have matured, the growth on the roots has also matured and slowed so it is less of a shock to the roots to cut them at that time.

People tell me that whilet they can recognise when most of their trees need root-pruning they are unable to tell when their Japanese Black Pines need to be done.  So here are a couple of tips.

Candles:  When the candles elongate and the needle tips are just peeping throught it is perfect time.  However as with most bonsai if the candle has opened up and looks a little like a shaving brush it is too late.  Leave them until about October and do them when their foliage has hardened

  1. off.
  2. If you are working a pine for the first time and don’t know what a candle is, then you

         should be safe to rootprune in October anyway.

Remember also to take care with Australian Natives.  Some are very sensitive to being trimmed at the wrong time, yet others, namely figs can be root-pruned all year round in the warm regions.  Natives have a six weekly growth cycle so watch for a flush of new growth, then when it hardens off it is safe to root-prune.  If you are unsure what ‘hardens off’ means, most new growth is a different colour, such as the lillypilly whose new foliage is pinkish, the Callistemon’s new foliage is a pale brown/pink, yet both trees’ mature foliage is dark green.

Now is also a good time to root-prune Azaleas.   They are best done either during, or immediately after flowering and they like an acid soil with a PH of about 4.5 to 5.

Although Azaleas love a cool moist root run they do not tolerate ‘wet feet’ and will succumb to rootrot if they are not given good drainage.  I use the same mix for all varieties of bonsai but I increase or decrease the humus in the mix according to the varieties individual needs.  When potting pines I don’t add any humus but when potting azaleas I add about one part orchid bark to 8 parts of my normal mix.  As mentioned above azaleas are acid lovers so fertilize them monthly with ‘Phostrogen For Acid Loving Plants’or ‘Miracid’.  Another way to maintain acid levels for azaleas and camellias is to add peat moss to the soil as it is slightly acidic.  I personally won’t use Peat in my mixes because if it dries out it becomes very hard to rewet and endangers the rootsystem.

Well that is ’your lot’ for this month, go forth and rootprune…….. and have fun! 
( By Carole Waller)


SUMMER CARE by Ray Chalmers

As Summer is in full swing, it might be a good time to evaluate your watering regime. There are many factors which can affect how much water your bonsai will require, the species of tree, its size, where it is located, the composition of your soil mix and of course weather. There is a lot that needs to be taken into consideration.

Different species of trees have varied water need requirements, swamp cypress will happily sit in a container of water, while pines will prefer slightly drier soil between watering’s. /t is important to find out what soil conditions each particular species of tree likes. Some species will require different watering amounts than others.

The size of your bonsai plays a factor in how much water it will require. Generally the smaller the pot, the faster it will dry out, requiring more frequent watering, this holds for shallow pots or trays also. Cascade style pots tend to have more soil in them and don’t tend to dry as easily as shallower pots. Mame and Shohin sized bonsai (up to 25cm in height) may require placing in shallow trays of wet gravel or sand during really hot days to slow down the evaporation process. This can also be beneficial to water loving species like swamp cypress.

Where your bonsai are located, will affect how much water they require. Bonsai located in full sun will dry out faster than those that get partial shade during the day. Full sun versus shading is a debate /’ll leave for a future newsletter, there are advantages/disadvantages and opinions vary greatly. It is again, also dependent on the species type to a degree, maples grown locally are likely to suffer burnt foliage if left in full sun. Another important factor to consider with location is wind protection. A hot dry wind can do a lot of damage in a very short period of time.

The composition of your soil mix impacts how fast it drains and how much water it retains. Carole has written an article about soil composition which can be found on the club website, well worth a read if you make your own soil mix. A fast draining soil mix will require more constant watering to prevent your bonsai from drying out too much. A soil mix that retains a lot of moisture, or doesn’t drain well, won’t require as much watering and can lead to problems with root rot. There needs to be a balance between wet and dry, to achieve healthy trees.

As it is Summer, it does tend to be hot and dry, however the past few years have been particularly wet. Even the past few weeks, we have had some storms with heavy periods of rainfall. It pays to keep track of the weather and in the case of storms, how much rain has fallen. Checking the condition of the soil before watering is the best way to see how dry or wet the soil is (sticking a finger into the soil about 1 cm is a good way to check this). Soil that is still damp, won’t require as much water(if at all), as soil that has dried out.   So watering your bonsai isn’t just a case of pointing the hose at them and giving them a soak. Take some time to learn the requirements of each of your trees, as they will be different.

Summer has also brought with it storm season and the risk of hail damage. Do you have protection for your trees or a plan in place to protect them in the event of a sudden storm? It may be worth getting to know your neighbour, so in the event a storm hits while your away, that protection can be sought for your bonsai to minimise any damage occurring.

Ray Chalmers