The Bonsai Year
North Island
New Zealand’s climate ranges from the Winterless North, through the warm and wet Waikato and alpine regions in the west of Canterbury to the cool South, with the next stop being Antarctica
This provides for a wide range of species being grown as bonsai which are more suited to one area than another.
It’s no good trying to grow Larches or Southern Beech North of Auckland and some of the more delicate species do not like the colder climate in Otago.
Here we have put together a few guidelines on what you can do with your trees at various times of the year.
THIS IS A ROUGH GUIDE ONLY – Your area may well be in front or behind these times.
The North Island tips are based on the Waikato region, The South Island tips on the South Canterbury region
January
Water! Water! Water!
December/January is the time to keep a careful eye on the water needs of your trees. Try to water in the mornings before lunch as watering at night leaves the roots of the trees sitting in water when they should be taking up air not water.
Shade from midday is a good idea for most species used in the art of bonsai. Pines and cedars are the main exceptions to this, as they love full sun even in the shallowest of bonsai pots.
This is the time to trim those shaggy maples you have been allowing to grow over spring. Pines can also be pruned once the needles have fully developed.
It is also a better time of year to wire trees that need shaping, as the wire won’t cut in so quickly, and trees often set in the new shape quicker.
Unless you are really keen, there is little point in feeding in December/January, as the flush of spring growth has passed.
When you are going on holiday get someone to check on your trees, even if you have an automatic watering system, as things can sometimes go wrong like blocked water jets, pots that have fallen over, or flat batteries in the timer. Check that the jets of your watering system are not blocked even if you are not going away.
February
February is still the time to keep a careful eye on the water needs of your bonsai.
If you usually water with the hose each day, watering occasionally by dunking the tree in a bucket or deep dish is a very good idea. Submerge the bonsai so the water is well above the soil level and leave it in the water till all the bubbles stop.
At this time of year many local councils have high chemical levels in the water supply, so allow the water to run out of the hose for a minute or two before watering your trees. Try also to water in the mornings before lunch, as watering at night leaves the roots of the trees sitting in water when they need to be absorbing air.
February is another time to repot species of trees that enjoy the heat like Pohutukawa, Figs, Jade Trees, and other tropical and semi tropical species.
This is now the time to do summer pruning of the extension growth on most species of bonsai (all those shaggy maples you have managed to resist chopping back for soooo long). Also continue trimming ‘Southern’ Trees like Chinese Elms, Zelkova, and Trident Maples back to 3 or 4 branchlets constantly. Pines can be pruned by removing the unwanted growth (which has developed from the candles produced in spring) once the needles are fully developed.
February is also the time to return to feeding your trees. Liquid or solid, organic or pure chemical. Your choice!
March
Re-potting of most species of tree can continue into March as there will be a second growth spurt in autumn allowing the trees to recover before winter. Remember to put newly re-potted trees in a position where they get shade from noon and shelter from strong winds.
As the temperature drops by the end of March, you can begin to wire trees that need shaping. You will need to watch that the wire doesn’t cut in though.
Feed your trees now. A one off top dressing of your favourite general purpose fertiliser will suffice, if you are not up to liquid feeding weekly (make sure you water well after applying Blood and Bone or Fish Meal to prevent yours, or your neighbour’s cat attempting to lick it all off). If you can find a low nitrogen feed start using that as the trees need higher Potassium and Phosphorus levels for winter protection.
April
Feed any trees that still have leaves, but don’t bother if they have lost their leaves as they are already dormant and will not use the food.
It is time to remove the old needles from Pines and Cedars.
Wiring can be done now as the flush of autumn growth is mostly over in the Waikato region.
It pays to put the cover on frost tender plants. Frosts can be devastating.
May
This is the time to do autumn pruning of deciduous trees once the leaves have fallen to improve their shape.
May is also clean up time after the leaves have fallen, as even bonsai can suffer re-infestation of insects and diseases if leaf litter is left on the surface of the soil or on the shelves.
A clean up spray for lichen and insects is a good idea this time of year too, if you are into spraying preventatively.
May is still a good time to wire trees to improve their shape.
June
Winter is here. Frosts can cause bonsai to dry out, so keep an eye on the water needs of your trees.
There is still time to remove the old needles from Pines and Cedars if you have not already done so.
Autumn/Winter pruning of deciduous trees can be done now, and early flowering trees such as Camellias can be pruned once they finish flowering.
Wiring can be done now as the trees will have plenty of time to set in place before spring growth causes swelling, and the wire to cut in.
June is clean up time. Remove moss at the base of your bonsai tree’s trunks. Using an old tooth brush while the moss is wet makes it quite easy. Spray your trees now if you’re into it. Spray for insects and lichen this time of year. There is still a need to clean away leaf litter from the surface of the soil, on the shelves around the trees and under the shelves too.
July
Time to prepare for springs re-potting season. Buy in, or gather the ingredients you need if you make your own mix, and make sure you have enough wire, string, and mesh to cover pot drainage holes. Make sure you can get to your selection of bonsai pots, in-case you decide to change a trees pot, and clear space in ‘The Shed’ to work, as it is bound to rain.
July is the time to lift any trees that have been growing-on in open ground or in the garden, and a good time to collect trees from the wild (with permission from the land owner of course).
In the Waikato region July is the time to re-pot Cedars. The timing is critical for the safest re-potting of Cedars. You have the time between when the buds on the top of the tree and at the tips of the branches start to swell, till when the buds show a little green only. A matter of only days in some trees so watch your Cedars closely. Once the buds on Cedars open it is too late, and re-potting could result in a lot of die-back or even the loss of the tree completely.
August
As the days lengthen there is still time to re-pot most things in the Waikato Region (other than cedars as it is probably too late for them).
Pines and conifers and some natives like Totara and Kahikatea are best re-potted in August.
Deciduous trees are best re-potted as the buds start to swell and can be safely re-potted up until the leaves unfold, which can vary drastically in the Waikato from late August to October.
September
Watch for slugs and snails as they will demolish the new leaves on deciduous trees very quickly.
Flowering trees like Camellias, Azaleas, and Wisteria can be re-potted in September or as soon as they finish flowering.
If you are not re-potting certain trees this year, they need nutrient or feed. There are heaps of options for fertiliser but whatever you choose, only use at the strength recommended, as more is not better in this case.
Check any trees that are wired, as the wire may need to be removed if it is cutting in. The trees may need to be re-wired if the branches are not set in place.
October
Check the wire on any of your trees regularly at this time of year as wire can cut into the bark in a matter of days with some fast growing species.
Watering is now necessary don’t just rely on rain.
Slugs and snails are out in force now. If you have pets then use ‘Quash’ Slug Bait sprinkled around the top of the pots of larger trees or on the shelf around the pot. There is an antidote for that brand if your pet is silly enough to eat any of the pellets. Others may use more ‘Green’ suggestions. You can go out at night with a torch and squash the slugs and snails but it’s a bit of a job when you have a large collection.
This is the time when all sucking insects are doing damage so spraying is also a good idea. Pyrethrum is a good general insect spray but once again there are lots of sprays on the market for different insects. Use only as directed on the packet.
Apply nutrient (or feed) your bonsai this time of year. Use fertiliser only according to the directions on the packet or bottle. More is not better. Do not fertilise bonsai that have been re-potted in the last 6 weeks or bonsai that are sick (unless you are sure the tree is sick because it is starving).
Trim ‘Southern’ trees like Chinese Elms, Zelkova, Trident Maples, back to 3 or 4 leaves constantly now. Leave trimming ‘Northern’ trees like other types of Maples, Beeches, Oaks, Hornbeams, and Pines till Christmas.
Flowering trees like Camellias, Azaleas, and Wisteria can be re-potted as soon as they finish flowering.
November
It is not too late to re-pot some hardy trees like Junipers, Chinese Elms, and of course Privets now. Just remember to shelter them from strong winds and too much sun.
Take care with the watering at this time as we can have long fine spells in November and your trees may be drying out more quickly than you realise.
December
Water! Water! Water!
December/January is the time to keep a careful eye on the water needs of your trees. Try to water in the mornings before lunch as watering at night leaves the roots of the trees sitting in water when they should be taking up air not water.
Shade from midday is a good idea for most species used in the art of bonsai. Pines and Cedars are the main exceptions to this, as they love full sun even in the shallowest of bonsai pots.
This is the time to trim those shaggy Maples you have been allowing to grow over spring.
It is also a better time of year to wire trees that need shaping, as the wire won’t cut in so quickly, and trees often set in the new shape quicker.
Unless you are really keen, there is little point in feeding in December/January, as the flush of spring growth has passed.
When you are going on holiday get someone to check on your trees, even if you have an automatic watering system, as things can sometimes go wrong like blocked water jets, pots that have fallen over, or flat batteries in the timer. Check that the jets of your watering system are not blocked even if you are not going away.
South Island
New Zealand’s climate ranges from the Winterless North, through the warm and wet Waikato and alpine regions in the west of Canterbury to the cool South, with the next stop being Antarctica
This provides for a wide range of species being grown as bonsai which are more suited to one area than another.
It’s no good trying to grow Larches or Southern Beech North of Auckland and some of the more delicate species do not like the colder climate in Otago.
Here we have put together a few guidelines on what you can do with your trees at various times of the year.
THIS IS A ROUGH GUIDE ONLY – Your area may well be in front or behind these times.
The North Island tips are based on the Waikato region, The South Island tips on the South Canterbury region
January
Water is the most vital thing you can do for your bonsai, watering in the morning before 8 am is best. As temperatures rise quickly [as they usually do in the South] they can be unpredictable, and very changeable with very hot days and cooler days mixed in. Late in the day watering can cause water marks on leaves. If you have to water later in the day use fine spray on the roots or dunk in a tub of water.
Semi shade is better for deciduous trees between the hours of 11am and 3pm [the hottest part of the day].
When you are going on holiday over Christmas/Jan/Feb period, sprinkler systems are fine but not always reliable. Well meaning neighbours asked to water bonsai sometimes remember the day before you come home to do so, resulting in dead bonsai. Alternatively, water well, bury bonsai in a damp place in the garden one or two inches below the edge of the pot, cover pot with a layer of sawdust or sphagnum moss, or bury in a sawdust bed. This will keep the bonsai moist for months.
Also another alternative for a one to three week holiday, water well by dunking, put pot into a plastic bag, tie at base of trunk leaving foliage sticking out the top, leave in cool place [like shower]. Do have a friend drop in occasionally to check on trees and watering systems.
February
Watch out for the leaf roller and bugs through January and February. Spray helps or the wonderful quick and painless squeeze between two fingers.
Watch the watering [as in the South often February / March can be hotter than January] if faced with hosepipe restrictions alternative watering is handy. Dunking in a tub of water, or tank water.
Repotting in the autumn – in the South late February is a good time to repot Cedars before the buds look like opening. Early March there are several species of tree that can be repotted at this time.
Because needle pull is coming over the next few months in pines prefer to be repotted in spring.
This is a good time to do corrective pruning and fine wiring which can be removed late winter / early spring.
Keep up with watering, start feeding mid February with a foliage feed.
March
Time to have a look at the aerial layering [done last September through to November] if developed good roots time to look at cutting of from parent tree. In the South trees need a couple of months on new root system to gain enough strength to get through winter so keep in sheltered, warm spot.
Getting colder at night, but warm days still – conifer growth has extended well so fine wiring will help with the tips of the branches.
When a tree has been repotted leave it in a sheltered spot for approx three weeks to recover. Alternatively string tie downs can be another option, by using cotton or hemp string to pull branches in the direction required, this method means leaving the string on until it rots.
Can do heavy pruning or cutting at this time of the year.
Feeding with favourite fertiliser throughout autumn, foliage feed is still good helping build up sugars and starches in your bonsai to get them through the long months of winter.
In late March Crassulas and figs are best brought inside.
April
Keep Pines and Cedars in full sun, buds can benefit hugely from good sunlight at this time of the year.
Early April is the time to do last of the repotting, as it is getting late in the year for repotting so do not take as much of the root system of the tree as you would do in the spring. As there is a variance in the South Island temperatures each area has its own time table on when and where.
Otago is putting on a brilliant show of colour in Maples, Larches etc.
Late April early May is the time to tackle old needles on pines and cedars, watch the wire on tips of conifers.
May
Autumn pruning after leaf drop, continued wiring of branch tips.
Start of the clean up, gathering up leaves that have dropped, late May a light spray of winter oil can help with getting rid of some pests, mosses and lichens on trunks. You can also use lime sulphur, at different times in the winter a monthly light spray can help trees. There are also quite a number of other products on the market that can be used.
Time also to put some of those frost tender trees into winter storage under shelves or in a sawdust bed – Maples, some Kowhai’s and Pohutukawas. Conifers at this stage benefit from more sunlight.
Good time to collect from the wild – Larch, Beech, Totara – make sure if collecting this time of the year to take plenty of soil with each tree that you dig up.
Great time to make Hypertufa.
June
Time to look at cleaning down benches and bonsai area.
Weather in the South is usually wet, cold, snow and frost. The smaller size bonsai need to be protected well – possibly the use of sawdust beds can help, sheltered place out of the cold wind protecting the pots can be important, as some ceramic pots with the build up of water in them and heavy frost can blow to pieces.
Look around nursery’s, exploring the “wilds” for those potential bonsai stock. In the South sometimes the ground is so frozen the spade wont go in to it, so choose your time wisely.
Review needs for the spring. Sometimes with a mild winter water can still be required so do a regular check on your bonsai.
Observe your trees for future changes of style.
July
COLD
Time to look at cleaning spare pots, straighten wire, cleaning and sharpening tools.
Good time to get books out and read and plan your future treasures beside a nice winter fire and listen to the wind, sleet and snow outside.
Winter can bring a change of colour in Conifers – some will go red, blue or grey and back to green in spring.
August
The last week in July will see a movement in some buds like Cedars and pines. Early August is the time to repot Cedars if not potted in Autumn, can be potted now before they start to open into bud, if left longer will have a needle drop.
Pines are best potted in August. Conifers, Juniper Media Blaauw, and Green Globe need to be repotted no later than the middle of August.
Time to lift trees out of open ground growing. Check wire on trees.
Repotting not done in autumn is best done August /September.
Root systems can benefit the tree with a soak in “seasol” before replanting.
Developing a new bonsai repotting can be done through until mid November.
Alternative feeding throughout the growing months is better as every fertiliser has different trace elements.
September
Time of growth, time of pinching which carries throughout the growing season. It’s also the time of wiring, feeding and repotting.
Azaleas and Rhododendrons start to flower, after flowering it’s time to repot and cut dead heads off, as rhododendrons, wisterias, azaleas and camellias set their flower buds a year ahead.
Other spring flowers like Pyracanthas, Cherries, Crab Apples – allow them to set their fruit [take fruit of these trees in June, which allows time to reset fruit buds for the following spring].
If developing structure in Maples and Larches keep a watch on the wires, start pinching back to 2 lots of new leaves on Maples and upward growth on Larches, allowing extensions on Larches to be trimmed off in November to half the length of the new growth on the small branches. This will stop “balling” on the tips and extend the small branches on the trees. Same method for Spruces and Cedars. Larches can have 2 growth times in a year – spring and autumn.
October
In the South we are still having a lot of bonsai flowering.
Water and feed.
Still lot of spring growth, usually high winds, so shelter for newly opened deciduous trees is required.
Can still repot Conifers, and other trees that require repotting.
Keep up with needle plucking, pulling Spruce and Abies Raglans extensions by reducing by half.
Wiring of smaller new growth on deciduous to improve the structure of the branches.
Check the candles on the pines.
Watch for the dreaded Liverwort. Treatment is spray with vinegar, because of the acidity of the vinegar it goes to a brown muss in a few days. Do not put too much vinegar on soil as can change the PH [sometimes a paint brush works if there is only small amount of liverwort].
November
Repot later flowering azaleas and rhododendrons, In the South it’s time to start pinching candles on the pines, down to 2/3 needles. Keep in full sun.
Still pinching, feeding, watering, remossing and tidying up trees. Pines and trees that have sacrifice branches are extending well.
Trees that have missed the repotting, take a root puller and around the edge of the inside of the pot put the root puller down to the bottom of the pot pulling up the tight edge of the root system approximately half an inch around the outside of the root ball in the pot. cut off and renew the soil. Feed well.
December
Good time to defoliate those well fed Maples, Oaks, Ginkgos in the South. Takes 6 to 8 weeks to grow into leaf again. Only do it on trees that are growing strongly and have been well fed in the spring. This will allow the leaves to regrow smaller. Don’t do this to a young tree as it will weaken it too much. Preferred method is to take the leaf off, leaving the stalk on branch and as the new buds develop it will push stalk off tree. Keep in the shade until new leaves appear.
Fine wiring can be still carried out on branch tips.
Watch out for those little nasty’s – they can chew up leaves quite quickly.
Watering, checking, watering, checking, watching recent wiring.
Lastly enjoy your bonsai.