Queensland’s 1 in 30 Year Record Cold Snap

Leonie Dufton, Ballandean, QLD 4382An East Coast Low weather system, delivering force 8 wind gusts, is rattling my windows. Australia’s east coast can experience around ten of these weather systems during the cool seasons. Today’s gales are causing minor delays to some flights leaving Brisbane, and major delays to filming with the ABC’s ‘Gardening Australia’ show. Close to the NSW/ QLD border, in Ballandean (QLD 4382), Leonie’s highland garden (pictured) lies under the a blanket of snow in a one-in-thirty-year weather event.

Question
Hi, Jerry, any tips on what to do with my garden when this snow melts? (My Ballandean garden pictured this morning).

Answer
Dear Leonie,

Wintry blasts like this were a feature of gardening in London. Knowing there would be at least two every winter helped me to prepare.

You are dealing with a one in thirty year event, which is different.

Expect gales damage. East coast lows pack winds up to the force of a category one cyclone. (Ex-Cyclone Oswald was category 1, and its slow movement scoured our coast, dumping seagrass over my roof. I live over 1 km from Moreton Bay).

A banana stem, ready to flower, was blown down across my fence this morning. I’ve trimmed off all its leaves, plus the stem section projecting from the fence into the front garden. This reduced pressure on the fence. The rest can go tomorrow.

Potted trees which blow down, are left down. Each time you pick them up there’s a risk they may blow down again. Each fall may add further damage. Restore order after the gales.

Anticipate potential sharp frost. If it occurs, it is most likely to occur the night when the gales die down. Dry, cold air may scorch the tips and edges of tropical foliage plants. Drape net curtains, shadecloth or old bed sheets over frost-sensitive plants, like young frangipani, chillies and tomatoes.

Sometimes East Coast Lows deliver flooding rain, an ironic twist to our traditionally dry season. But they were the most significant annual falls of rain, twice filling my near empty rainwater tank during the 2004 – 2010 drought.

In freezing weather, place a tennis balls in every pond, water butt, cistern and water feature. They act as shock absorbers, important because as ice forms it swells, so instead of the rising pressure ending up fracturing rigid walls (like ceramic bowls or concrete), they remove the pressure.

Drain hosepipes and irrigation systems. If they freeze solid, the walls can be ruptured as water swells into ice.

Flowers can be protected from frost damage by misting them with water at sunset. The ice protects the flowers from the worst frost damage. I grew up seeing this trick applied by my great aunt and uncle Plumbridge in London. They had a stonefruit orchard, and spring blossom often needed protection from late frosts.

Every winter in London, I lined my greenhouse with bubble-wrap. Useful frost-protection.

I moved potted plants away from windowsills. If they are shut between a curtain and a window when the temperature plummets, delicate plants (like ferns and foliage plants) can get frost-burned. We had many weeks when the condensation forming inside windows froze solid.

If leaves of trees, shrubs, cycads, palms or bamboo die back, I tend to leave the dead foliage on until spring. Even dead leaves afford some frost protection and a little shelter from biting, desiccating winds. Wynnum (QLD 4178) is allegedly a ‘frost-free’ suburb, yet I have experienced five frosts of -0.5C, two occurred one winter prior to an Open Day event. Tidying took four sweeps of the garden, because foliage doesn’t always die back instantly.

If succulents, like cacti or frangipani, are burned or frozen, cut them back as soon as the stem tissue inside starts turning brown. It’s decay. Juicy tissue allows decay to spread fast, so cut back to green, healthy tissue. Dabbing powdered sulphur on wounds retards fungal attack. That saved many of my cacti during London’s bitter winter of 1979.

Way back in the 1960’s, my family home was entirely heated by coal, so we kept houseplants and cut flowers well away from fireplaces. Fires gave us plenty of hot cinders, useful for sprinkling over snow-covered or icy steps, paths. Cinders were great because they added grip to frozen surfaces. The sloping driveway was a priority.

Salt was used as a last resort to remove persistent ice from steps. We knew that salty water runoff is toxic to plants. Local councils in London often stockpiled ‘rock salt’ beside street trees. This was used to keep roads open. In a sudden thaw, snow meltwater running through the salt  killed the tree’s roots systems.

I provided tailored frost protection for delicate evergreens, like Aleutian Maidenhair (Adiantum pedatum), Algerian Iris, Christmas Rose, Japanese Holly fern and Polypodium ferns. I placed individual panes of glass, resting them horizontally on bricks. I packed straw around the bases of these plants.

My Australian-effect front garden took a day to prepare for winter. On the first week of December, New Zealand Cabbage palms, (Cordyline australis), grown to resemble grass trees, were trained into single stems. The leaves were gathered upwards, held back by hessian straps then the entire crown would be wrapped in hessian until spring.

Silver Wattle, Acacia dealbata, had a triangular enclosure erected around its base. Formed by stout wooden stakes, the enclosure was made with a roll of hessian. Inside, the bottom 60cm was filled with loose, lightly packed straw. This insulating the base of the tree against freezing cold. If the crown was killed by cold, this wattle reliably suckered from the base in spring. Similar, but smaller, enclosures protected the Grevillea juniperina subsp. sulphurea, Crinkle bush (Lomatia silaifolia), and Crimson Bottlebrush (Callistemon citrinus).

Do keep yourself and your livestock warm. We put a room heater in the guinea pigs’ shed, keeping them heated to 10C. When temperatures dropped to -10C or -15C, we evacuated the shed and everything took shelter indoors.

Blythe Hill, Brockley, London, 1981 - 1

Jerry Coleby-Williams
17th July 2015