In the deep of mid-winter
I ALWAYS snicker a little when friends head for Far North Queensland in May - to get away from the cold, they always say, with a shiver.
Cold? Our winter is delightfully mild, with minor frost (maybe) and beautiful sunshine.
Anyone who has ever lived with true cold knows how destructive it can be in the garden. Hard frost severely limits the range of plants that can be grown - and will kill anything that is the least bit 'tender'.
Here, it is only the true tropicals, like Mussaenda philippica Queen Sirikit and some ornamental gingers, that need extra care. Curcuma gingers will have died back naturally, but the evergreen heliconia and costus species may need to be protected, with hessian tied around some garden stakes.
Not all gardens will be affected in a mild frost, as the cold, dense air rolls down slopes and "pools" in low areas. Like the hessian shelter, trees overhead can protect plants below, while fences and walls may prevent cold air from moving away from your garden. Frost is usually patchy and hard to predict, but experience will show you which areas are vulnerable.
If you see a cold night forecast, you might like to temporarily cover some plants, especially those that put on late growth in our wet autumn. Any sort of cover will do - old sheets, shadecloth, etc. Even a bale of straw or cane tops can be a help if you scatter the loosened straw over the foliage.
You might wonder why your garden gets frost when the overnight temperature remains above zero. That is because the Bureau of Meteorology measures the air temperature about 1.5m above the ground. (There is a standard height for the base of the sensor shelter.) Since the cold air falls, it can be markedly colder at ground level.