Seasonal Jobs by Dennis McDermott Bsc.
Perhaps the most delightful months of the year. Most plants spring into life and the whole development of the tree is set in place. So it is vital that they get off to the best possible start.
The fresh new growth of deciduous trees and blossoms of flowering plants make a spectacular picture on the benches. Some of you have already enjoyed the late winter blossoms of the Japanese Flowering Apricot, Cherry and Quince. The foliage on these plants develops at a quick rate straight after flowering. It is very important to trim back this early aggressive growth they put on in spring frequently to increase the branching volume in those respective plants. The second wave of flowering colour is on the way. People who have Azaleas, Crabapples and Wisterias will be hopefully currently admiring them in full flower. There are plenty of other flowering plants in spring but these three plants are certainly the big three that make a huge impression in spring at their peak.
Growth is vigorous in spring so pruning is a major activity. The following bonsai will require almost constant pruning:
Maples. Tip pruning through spring will result increased ramification and shorter internodes.
Crepe Myrtles. Regular tip pruning will also result in increased ramification and shorter internodes. However since they flower on terminal tips pruning should cease by the end of November to allow flowering buds to develop.
Japanese Black Pines. Timing of pruning on JBP is critical. In September removal of spring candles should be undertaken. Timing is critical to ensure that the maximum development of the tree is obtained. They should be removed as soon as any tiny green tips appear anywhere on the candle (For further guidance please see the notes on growing JBP)
Chinese Elms. All of the elms, including Zelkova grow very vigorously in spring and shoot pruning is vital to both develop and maintain the style. Similarly the Privets will be in vigorous growth.
Azaleas in Sydney are regularly attacked by leaf sucking insects such as 2 spot mite, leaving the leaves both unsightly and unable to properly perform. A spray program should commence mid-September and continue to the end of summer. Satsuki Azaleas are amazing in flower. However in Sydney they flower later than the others (October) when the weather is warmer and the humidity is high. High humidity will result diseases destroying the flowers. As soon as the flower buds begin to open place the tree under cover during flowering (don’t forget to hand water on the soil only
Wisteria. They can be spectacular in flower. Remove spent flowering heads as soon as the flowering is finished. Long thin canes (whips) will develop. These are basically designed to allow the vine to grow extensively and gain a hold. They will be unlikely to flower. They should be cut back leaving the 2 or 3 unopened buds located where the whips emerge from the plant. These remaining buds will produce compact growth and particularly flowering material. NOTE: not all wisterias will ever flower and you should obtain material that has/is flowered to ensure that you will get flowers in the future.
Fig Trees. By October we receive some consistent warm weather, thus it is an ideal time to get stuck into your Figs. They can be pruned back and re potted all at the same time. Figs really thrive in an open mix. Figs are very tough plants but are prone to rotting if planted in a very fine poor draining mix. The new growth tips should be pinched back and large leaves cut off. If you wish you can even totally defoliate your tree now by removing all of the leaves by cutting the petiole (leaf stork) which is attached to the base of the leaf in half. As the new leaf emerges it will push the old petiole away and you will soon have additional growth buds and small glossy new leaves and more in proportion with your tree. It is important to spray with water the milky sap that appears when cutting any part of the tree. If it is left to run down and settle on any part of the tree it can leave an unattractive stain. If you have any really overgrown Figs do not hesitate in cutting them back extremely hard to get the growth closer to the trunk. It is always advised to re pot the tree at the same time and add plenty of fertiliser to the potting mix to give the tree a well and truly fresh start. Finally and most importantly Figs, with the exception of the Sandpaper fig, should be kept in the sunniest position you can find for them to get optimum growth and development out of them.
It is important to increase your fertilising frequency now. Slow release fertilisers combined with ORGANIC liquid fertilisers make an ideal fertilising combination. Freshly repotted trees should've had some slow release granular fertiliser added to the mix to give a slow and steady food source to your tree over the next 4 to 5 months. Remember more is not better. I have seen plenty of trees killed over the years with over fertilising particularly from chemical high nitrogen fertilisers.
Native trees should be fed in the same manner as the exotic trees. It is not necessary to use special native fertilisers. In 30 plus years of growing bonsai I have not had any problems with natives using standard fertilisers. However do not use fertilisers with excess phosphorus such as those recommended for encouraging flowering.
Weeds are a constant problem in pots especially in spring and summer. They should be kept under control as they rob the tree of nutrients.
Keep an eye on some of the wiring that you may have placed on any of your trees over the winter. Foliage growth may cover wiring and you may become unaware that wire is on a particular tree. It is always an idea to put a coloured tag in the soil of the pot of your tree to remind you that it is indeed a tree that has wire on it. Then simply remove the tag when the wire has been removed. Monitor the wire you have placed on trees weekly this time of year as the growth of trees thickens at an alarming rate and you don't want to spoil your wiring efforts with deep scars in the branches of your trees because it has been left too long.
Finally, spring signals the start of a large itinerary of Bonsai exhibitions and garden shows. Try to get to as many as you can. At Bonsai exhibitions you will be able to observe a wide variety of plant material used for Bonsai and gain ideas on styling particular plant varieties. Garden shows are also of an interest to attend as most often many new release plants are launched and some may be new hybrids of plants we currently use but offer alternatives to flower colour, leaf shape, growth rates etc. Go and explore and hunt out your next Bonsai treasure!
Once spring flowering plants have finished flowering all dead heads should be removed, unless you wish to have them fruit.
Windy days are typical of spring while humidity is relatively low in Sydney. Keep a close watch on your trees as they may dry out very quickly.
The School of Bonsai's Annual Exhibition and Show at Ray Nesci Bonsai Nursery is an excellent way of seeing what other Bonsaiists are doing. It is free entry to all and there are continuous Bonsai demonstrations, quality Bonsai and Suiseki on display and a Sausage Sizzle taking place. So get active we'd love to see you there!
Summer is one of the trickier seasons for Bonsai. So many people blame the excessive heat for the loss of their plants at this time of year. Yet what actually kills the plants is a lack of water, not the heat. If you know how much water certain Bonsai in your collection require and are also organised to get the required amounts of water to them, then you should have not loss any of your Bonsai but leaf damage to some such as the maples is difficult to avoid. On those excessive days of hot temperatures most of your Bonsai will have to be watered twice a day. Some compositions such as rock plantings can be almost impossible to keep moist on days of excessive heat and should be moved to a shady position until the excesses of summer diminish. The same also goes for minis. It's impossible to keep something with so little soil moist on days of high 30 degrees to 40 degree days. To also aid in keeping the humidity up to these little wonders, you can place them in a tray and fill it up with sand and bury the pots in the sand up to the rim. When you water them, water will be retained in the sand and therefore keep them moist for longer periods of time. You can also place sphagnum moss over the top of the pots which will also help to keep the soil surface cooler and retain moisture longer. Other plants to give extra attention to in the summer include Australian Natives, pot bound trees, forest settings and root over rock compositions. Why root over rock compositions? Well, they are generally planted in shallow trays for one, and secondly the heat that builds up on the rock during a summer’s day can be tremendous, and this radiating heat can scorch the roots on the rock. So it's a good idea to wrap a cloth around the rock to provide a cooling buffer for these exposed roots.
Another thing to consider is to have some coverings such as moss or pebbles over the soil surface of your Bonsai. This acts as a mulch and helps retain moisture longer. You can add coarser and more traditional type mulches to your plants in plastic pots. Accurate watering is crucial, misses are fatal during the summer. December/January is a time of the year when people take short breaks away or extended holidays. If you instruct someone to water your Bonsai for you whilst you’re away and they haven't had any experience in watering Bonsai, then make sure you show them what’s required. It's amazing what some people call watering! They may also have some misconceptions on how much water Bonsai require. So set them straight to avoid extreme disappointment upon your return.
By the middle of January most soft deciduous trees have at least some burnt foliage. It is an ideal time to defoliate some of your deciduous trees to get new fresh foliage. The other benefit of defoliation in deciduous trees this time of year is the production of fresh leaves to provide optimum autumn colour in the proceeding months. Summer can really batter the leaves of broad leaf deciduous trees such as Japanese Maples. If Powdery Mildew doesn't discolour them, then the scorching Westerly winds can burn the tips and distort the leaves no end. Leaving a mangled mess with little hope of attractive autumn colour being produced. Remember proper aftercare of defoliated deciduous trees is crucial. If you have some days of very excessive temperatures whilst a tree is still bare of foliage and they are left out in a full sun position the bare branches or trunk could get burnt. So a semi shade area should be provided for them on any days of extreme temperatures.
Don't feel you have to wait till after Christmas to remove larger leaves on some deciduous trees. You can and it is advised to continually remove larger leaves from trees that are notorious of blocking a lot of light to lower branches with their broad umbrella canopies. Liquidambars, Oaks and Japanese Maples are just some of the more common trees that are guilty of this.
Something that you will also have to keep up with is fertilising. With extra watering fertilisers leach at a faster rate so make sure you are maintaining a steady organic liquid fertilising program right through the summer.
Most Leptospermum (Ti Tree) and Callistemon (Bottle Brush) species have ceased flowering and will now produce a seed capsule. Now is an optimum time to give these two species a good pruning back and the removal of any spent flowers so no energy is wasted in producing a seed capsule. Baeckea can also be pruned back straight after flowering late in the summer and re potted.
Keep up with monthly spraying of your azalea's for Lace Bug. This pest that distorts the leaves and weakens the plant from sucking the sap from the leaves should be prevented at all cost.
Weeds are in abundance after some favorable conditions and should be removed on sight. They rob nutrients and moisture from the soil of your plants and therefore restrict their development.
In our Sydney climate many trees need considerable moisture to thrive, some can stand in a water tray throughout the summer months. They include Wisteria, Banksia, Swamp Cypress, Callistemon and melaleuca.
Be wary of the powerful summer storms, they can knock trees off stands with ease or even break off individual branches. Hail is not unknown with summer storms.
Maintain tip pruning of the Figs. If you dislike aerial roots which can quickly form in the moist conditions of autumn then don’t hesitate to remove them.
If we see any early autumn colour on our trees. It is because the plant has run out of vigor for the season. Trees that are pot bound or even trees that missed re potting the previous season will have a shorter growing season. Going into early autumn colour won’t do the tree any harm but you have definitely had a reduced development period on that particular tree for the season.
Trees with autumn colour can make some truly stunning images. If you don’t have a lot of trees that produce Autumn colour then you might want to consider adding some of the following to your collection. Maples, Liquidambars, Miniature Virginia Creeper, American Hornbeam, Pin Oak, Pear, Chinese Tallow, Chinese Pistachio, Nyssa, Chinese Quince, Zelkova, Gingko and many more!
The milder months of March and April provides us with an opportunity to do some re potting. Plants under consideration are Australian Natives, Conifers and other general evergreen plants. Tropical evergreen plants such as Figs, Murrayas, Gardenias etc. should be re-potted during the warmer months. Re potting of Pyracanthas and Cotoneasters is best left until after their berries have past their peak in late April. Another option is just to wait till late August/early September.
It is very important to really maintain your fertilising of your plants throughout autumn. Plants are looking to store plenty of energy at this point of time and you can assist them with this by giving them regular nutrient uptake. Elms which commonly have some die back coming out of the winter can have that reduced if they don’t go into winter under nourished.
Pomegranates have been in flower and will be producing the very attractive fruit soon. Keep an eye on fruit that develops on small or weak branches as the fruit could weigh the branches down to a point where it will snap off. If any of your fruit bearing trees produce excessive amounts of fruit it may be an idea to thin out some of it so it doesn’t take too much energy out of the tree. And it’s a good idea to remove all the fruit on the plant after it has passed its peak.
If you are looking at putting some deciduous trees into a forest, autumn is an ideal time to select your specimens. A lot of deciduous trees we use for forest plantings such as Maples, Liquidambars etc. are seed grown, thus you will get seedling variations. One variation you will always get in deciduous trees is the type amount of colour of foliage each tree produces in autumn. So hunt around for the look you want and have them ready for planting in winter.
Spring and the growth and development it brings can seem quite a distance away at present but the preparations for the best possible results for then in fact start now and over the next few months. We definitely want trees going into dormancy as healthy as possible. So definitely maintain your fertilising programs right up until autumn.
Regular re potting is also a huge factor in maintaining the vigor in plants. Your faster growing plants should be re potted on an annual basis. Trees that you are looking for rapid development should be getting potted up into the appropriate pots that will aid your aim for them. Black plastic pots, Mica pots or deep ceramic pots will certainly provide the root systems of those trees with plenty of volume to make a huge impact with the possible rate of growth of your tree. Ideally the shallow ceramic pots should only be utilised for Bonsai that are in refining stages, certainly not development stages.
Do not forget to take care of the perceived smaller issues with your Bonsai at present. Tend to pest and disease as soon as first sighted. Aphids can be in abundance and will be seen appearing on the tips of new growth on quite a variety of trees, sucking on the sap and weakening the new growth. Although not life threatening to your Bonsai they are detrimental to your trees development and should and can be quickly eradicated with Confidor.
Remove any browning off of needles in dense areas of conifers such as Junipers and. Apart from giving your tree a more tidy appearance and reducing possible havens for pests. It will let in more light for lower branches and allow possible back shooting to occur.
If getting enough water to your Bonsai is the main challenge in summer then I’m sure some of you will also agree that getting adequate sun light to your Bonsai in late autumn/winter is the other seasonal challenge. Everyone’s situation is different. But normally in everyone’s backyard there is always at least one area where the Sunlight is extremely poor in winter. Conifers in particular will badly suffer in these types of situations and must be moved to areas where you can give them the most sun possible. Figs and trees already deciduous on the other hand can be low light tolerant and could be a suitable substitution if space is scarce.
Also reduce your watering as required to ensure that the trees do not remain too wet! If the potting mix is staying constantly wet and not slightly drying out in between the periods that you water they will be prime candidates for rotting root systems and all sorts of fungal problems. The golden rule in Bonsai is to observe each tree as an individual and not generalise. Autumn and winter will be your real test of your soil mix. If it remains too wet despite careful watering it will need to be altered, perhaps with additional river sand added to assist drainage.
Towards the end of May/early June most leaves on your deciduous trees would have fallen and accumulated around the base of your pots. If left in this state through Winter the piles will become a compact haven for pests and disease, which can infest your trees in the upcoming Spring. It is an opportunity during this time to do a good clean up in general. Benches can be brushed, scrubbed and even sterilised with a diluted solution of Dettol. The outsides of pots can be washed and wiped of soil, algae etc. that may have settled during the season. The feet of pots which usually attract green algae can also be scrubbed off to maintain optimum appearance. Spent fruit on Pyracantha and Cotoneaster’s can be removed, as well as any old disfigured leaves. Not only on these species of plants but most other Evergreen trees.
If you are in an area where you could possibly get frosts you should start to make preparations to protect frost prone plants such as Figs. Place them where they can get some protection.
Finally keep an eye out on flyers for various Seminars that pop up in Winter. There is always something new you can learn and always an opportunity to get a problem you may have with one of your trees solved. Seminars are for ALL Bonsai enthusiasts no matter what level your knowledge or skills are. It is also a great opportunity to get to know other Bonsai enthusiasts from other Clubs and share experiences and ideas.
The cooler weather is now in full swing. If not already done preparation should be made to protect Figs and other sensitive bonsai from the frost if you live in a frost prone area. If you only have a couple you might then want to shift them inside the house, verandah or any other protected position on selected nights when frost looks likely to develop. Cloudless still nights are the ones that usually promote a ripper of a Jack Frost!
Not much will be happening on the majority of your trees over the next couple of months. Deciduous trees will be providing you with dramatic silhouettes and possibly highlighting areas of your tree to work on for the following season. Some Conifers will get a bronze tinge to their foliage and other Evergreens such as Cotoneasters and Azaleas may get some red and orange colouring depending on how cold it gets this winter. Some of these changes can really worry people, but I can assure evergreen trees especially the JBPs.
Ideally most of your trees should be re-potted prior to bud swell. However if you have many deciduous trees to be re-potted, time constraints can make this ideal approach near impossible. So you may want to start re-potting some early shooting or Winter Flowering trees in June/early July. Trees that should come under consideration for early re-potting are; Mulberry, Chinese Elm, Japanese Flowering Cherry, Japanese Flowering Apricot, Japanese Flowering Quince, Chinese Quince, Pomegranate and pears.
Winter is an ideal time to do wiring on Evergreen or Deciduous trees. With the foliage disappearing from deciduous trees it makes it exceptionally easy to see the branch structure and wire to an organised shape. Because of the lack of growth on our trees the wire can stay on longer and therefore have a greater chance of successful shaping.
For a lot of the faster growing deciduous trees annual re potting gives you strong steady growth on a consistent basis on your tree. Some trees, if left 2 or 3 years without re potting can really have a quiet few years in development. So particularly if you have a younger tree and are looking for strong vigour keep them re potted regularly. This will also depend on the amount of sunlight your trees get as any deciduous trees kept in a part shade position will certainly not fill its root system in a pot nor put on top growth compared to a similar tree in full sun. The use of different potting mixes can also be another variable for consideration.
During re potting work you may have the misfortune in finding Curl Grubs in some of your pots. For those of you who are not familiar with this destructive pest they have a white body an orange brown head and strong mouth parts and usually rest in a "U" shape. They chew on the trees root system robbing it of its fibrous roots. I feel the best prevention of major damage is early detection. Detection can be made by noticing a lack of growth on your tree or inconsistent growth, dieback on the tips of branches, loose unstable trunks or if you push your finger through the soil surface and it moves down too easily. Unfortunately a lot of the time you only realise when you sight them during re potting of a tree. When you do find them remove every single one of them large or small. They can get wedged tightly right up into root systems so you may have to shake all the soil out to get them all.
If you suspect that some may be in your tree but it is not the right season for re potting I would suggest you try and drown them in a weak solution of Condy’s Crystals. Totally submerse your tree for a day or two and some will crawl out of the pot and others will just drown in the root system.
After re potting a dose of Seasol will help the root system get back into full swing at a much faster rate as well.
By the end of August early shooting deciduous trees such as Elms and Maples can have their first pruning to encourage multiple branching rather than long elongated growth. Elms can have their growth go out to up to 4 sets of leaves and then be reduced down to 1 or 2 sets of leaves. And the ever-vigorous Japanese maple should have the centre pinched out after it has put out its first set of leaves to keep a tight internode structure. Any noticeable die back in the branching from over the winter should be pruned off to maintain a tidy structure. Make sure your trees are adequately spaced from one another on the benches so the growth of one bonsai doesn't inhibit the growth of another. You may have adjusted a certain tree's position in your backyard for winter so don't forget to re-work the positioning of all your trees for the coming warmer months ahead.
Most of your deciduous trees re potting would have been completed, however from mid-August through to mid-Spring is an optimum time to re pot some evergreen trees. Some species suitable for this period include Privet, Olive, Pyracantha, Cotoneaster, Corokia, and Buxus among others. Most Australian Natives are also suitable for re potting during this time before they put on a growth spurt. Conifers in general can also be re potted with priority to Pines, Cedrus and Picea species. Juniperus, Chamaecyparis and Cryptomeria species can also be re potted but it is not as crucial to fit them in this period as they have a more flexible potting period of well into spring till early summer.
Fertilising can be stepped up as well. Trees recently re potted would have had some slow release fertiliser applied in the mix. However it doesn't hurt to supplement with some organic liquid fertiliser feeding every 2-3 weeks. Try and use 2 or 3 of different ones in rotation as most often different fertilisers have different volumes of trace elements.
If you have had Figs in a protected position over the winter or under shade cloth to protect them from frost they can now be repositioned for the coming spring. Figs (except sandpaper figs) really thrive in an open full sun position, so if you want that vigorous strong growth, shift accordingly.
Companion plant material such as Blood Grass and Bamboos that have died down over the Winter to a withered and dried appearance can be cut back down to ground level. This will create a much fresher tidier look when the new shoots start coming through in the spring rather than intermingled with the old withered shoots. To bring the new shoots on quickly the plantings should be placed in full sun and liquid fertilised regularly.
Finally, with exhibitions coming up, now is the time to isolate trees that are to be displayed and give them some extra attention. If the moss has died off during the winter, new moss should be reapplied and given ample time to establish before the exhibition. If moss is hard to find, a thick covering of pebbles will do a similar job. When pruning your tree make sure it is done well before the exhibition so the tree has ample time to fill out again and not look freshly cut. Thoughts on display tables or mats should be considered as well as companion plants to complement your Bonsai. Early preparation saves a lot of worrying at the last minute.