Winter — the green

For six months of the year Adelaide argues with its own reputation. Forget the sunburnt, water-restricted city of the tourist brochures: from roughly June to August, the belt of high pressure that parks over southern Australia every summer slides north, off the bottom of the continent, and the door swings open. Through it march the cold fronts of the Southern Ocean, riding the westerly winds that sailors call the roaring forties, and the region gets the one thing its whole ecology has spent the dry months waiting for: rain, arriving often enough and reliably enough that a colonial surveyor could draw a line across the map of South Australia based on exactly how much of it a given stretch of country could be trusted to receive (Cowling et al. 1996; Goyder 1865).

The country answers by turning green almost overnight. Paddocks that were dust-coloured in April flush with pasture grass, and in the surviving remnants the native tussock grasses and daisies that spent the dry season as dormant rootstock underground come back exactly on cue. Up in the ranges the transformation is more dramatic still: the range-front creeks, dry cobbled trenches all summer, start to run again, and the Torrens — a stream so unreliable it disappears every summer — briefly remembers what a river is supposed to do (DWLBC 2003). Walk a gully after the season’s first solid soak and you will likely find fungi where a fortnight ago there was only leaf litter, pushing up through the mulch overnight — the visible tip of the fungal partnerships that spend the rest of the year working, unseen, underground.

None of this greening is only for show. Winter is when the whole system does its banking. Reservoirs behind the range front fill fastest now, and under the plains a couple of dozen managed schemes divert winter stormwater and treated water down into the confined aquifers the city will draw on for the next nine dry months (DEW 2021). Plants run the same trick in miniature, building the root reserves, seed banks and soil moisture that will have to carry them through summer with no help at all. Winter is not a holiday from the dry. It is the dry’s own preparation season — and every green paddock, running creek and fresh flush of fungi between June and August is a down payment on staying alive come January.

Remember that, next time an Adelaide winter feels grey and unglamorous. It is the half of the year in which a coast running out of water each summer quietly puts some back.