Preventing Frost Damage In Australian Native Plants
I was reading some past copies of Journals from interstate groups of the Australian Plants Societies. I came across an article by Rodger Elliott in ‘Native Plants for New South Wales’. It was titled ‘Can we prevent frost damage?’ According to Rodger there are a number of strategies we can use to minimise the damage like many of our plants suffered last winter. Plants which are labelled as being frost hardy have the proviso added ‘in years of normal rainfall’. So in times of drought the likelihood of frost damage is increased. Now is a good time to take stock and perhaps move plants which may be at risk of damage and plan other precautions for next Autumn.
Frost damage can occur in some plants at about 1-2 degrees C, in others at about -4 degrees C and more at -8 degrees C.
Some Ways To Minimise Frost Damage
- Only cultivate frost tolerant plants.
- Look for areas where frost does not occur and use these places to grow frost tender plants.
- Do not apply nitrogenous fertilisers after mid summer in frost prone areas.
- Frost damage occurs when cold air is unable to flow away from an area. Make sure weeds are removed and mulches are flattened rather than heaped around plants. Hedges can prevent the free flow of air.
- Keep soils moist.
- Gravel and screenings are better mulches in frost prone areas.
- Do not prune in winter or spring until frosts have finished for the season.
- Hessian is a good cover to provide overhead protection. Do not use plastic.
- It has been shown that seaweed sprays strengthen plant cell walls and therefore have a beneficial effect in protecting plants from some frost damage. These are also thought to assist plants to withstand excessive heat.