A plant that races away in October and sulks in July is not being difficult; it is reading the same cues it has always read. Day length, temperature, winter chill and the moisture in the soil tell it when to grow, when to flower and when to rest, and a gardener who times feeding, planting and pruning to those cues gets far better results than one who follows the calendar. This guide explains the cues, how they play out across Australia's climates, and which jobs belong to which season.
The four cues plants read
Day length
Many plants measure the length of the night and use it to decide when to flower: chrysanthemums, poinsettias and kalanchoes flower as the days shorten, while many summer annuals wait for long days. Shortening days in autumn also tell deciduous plants to shut down, and cooler temperatures and shorter days trigger the pigment changes that produce autumn colour, a process explained in our guide to plants that change colour through the year. Our guide to evergreen versus deciduous trees explains what that difference means when you are choosing plants.
Temperature
Growth runs on enzymes, and enzymes work within a temperature band. Below about 10 degrees most garden plants barely grow; above about 35 many shut down to protect themselves, which is why a Perth or Adelaide garden can stall in January as surely as a Canberra one does in July. Soil temperature matters as much as air: roots grow in warm soil, which is why autumn planting works so well here and why palms planted into cold soil simply sit. Extremes at both ends need managing, and our guides to frost-tolerant plants in Australia and leaf burn and heatwave protection cover the practical responses to each.
Winter chill
Deciduous fruit trees, peonies, lilac, wisteria and many bulbs count the hours below about 7 degrees over winter and will not flower properly without enough of them. That is why apples and cherries crop in Tasmania and the tablelands and disappoint on the Queensland coast, and why low-chill varieties exist for warm climates.
Soil moisture and nutrients
Roots take up nutrients dissolved in soil water, so a dry plant is a hungry plant whatever the soil holds, and a waterlogged one cannot breathe to take anything up. Soil life is most active in warm, moist soil, which is why spring feeding does so much more than winter feeding. Watering needs change considerably as the weather cools, and our guide to adjusting your watering schedule in winter covers the transition.
The growing seasons across Australia
| Region | Main growing season | The quiet season |
|---|---|---|
| Tropical north | The wet, November to April | The dry, with irrigation |
| Subtropical coast | Spring and autumn; summer for tropicals | A short, mild winter |
| Warm temperate (Sydney, Perth) | Spring and autumn | Midsummer heat and midwinter |
| Cool temperate (Melbourne, Adelaide, Canberra) | Spring to early summer, autumn | Winter, with frost inland |
| Cold (Tasmania, highlands) | Late spring to early autumn | A long, cold winter |
The practical upshot is that most of Australia has two growing seasons a year, spring and autumn, with a lull in summer heat as well as in winter cold. Gardens here peak in October and again in April, and a bed that looks tired in late January is behaving normally.
How plants cope with the off season
Deciduous plants drop their leaves and wait. Bulbs and many perennials die back to a storage organ underground and reappear when the cue returns. Mediterranean plants such as lavender and olives grow through the cool, wet months and rest in the summer drought, the reverse of the lawn. Many Australian natives do the same, growing in autumn and spring and holding still through summer, and tropical plants grow whenever it is warm and wet and stop when either runs out. Knowing which pattern a plant follows tells you when to expect growth and when a lack of it is nothing to worry about.
Working with the seasons in your own garden
- Plant in autumn and spring, when soil is warm and the weather is mild, so roots establish before the plant faces stress. Our guide to the best time to plant a tree in Australia applies exactly this thinking to one of the most consequential decisions in the garden.
- Feed at the start of a growing season, not at its end, and not at all in midwinter; fertiliser a plant cannot use sits in the soil as salt.
- Prune by when the plant sets its flower buds, not by when you have time: old-wood flowerers straight after flowering, new-wood flowerers in late winter.
- Water by feel through the transitions, because the same pot can need half the water in May that it needed in February.
- Accept the quiet months. A garden that looks static in July is not failing; it is doing exactly what it should. Planning for that period, by including evergreen structure and plants that carry winter interest, is what separates a garden that works year round from one that peaks for six weeks and disappoints for the rest.
Conditions vary enormously across Australia, and your own notes on when things flower, flush and stall in your garden will always beat generic advice.
Ready to plant?
Browse our seasonal favourites, add year-round structure with evergreen plants, or introduce autumn colour with deciduous trees and plants.
