The Bonsai Year – 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


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.


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.


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.


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.


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.


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.



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.


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.


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.


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].


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.


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.