How do you prevent frost damage in the home garden?
Preventing frost damage in the garden can sometimes prove to be a little tricky, but there are some easy ways to keep yourself prepared!
Always pay attention to the forecast! The Bureau of Meteorology (BOM) website has a lot of great information that can provide the home gardener with current weather forecasts relevant to the Australian climate.
Cover up! Covering tender plants such as young seedlings, annual flowers, vegetables, and herbs can prevent their foliage from being burnt at the peak of frost. Cloak soft foliage and frost-sensitive plants as they are more likely to be affected by heavy frosts. Drape cloths over garden beds that are most likely to be affected.
Soft perennials and Hebes, being covered to prevent frost damage.
Get up, beat the sun and water!
The most damage caused by frost is when plants are still covered in ice, and the sun shines on their foliage. Soft foliage plants will go translucent and can even turn black! The best prevent damage is to lightly water plants covered in ice before the sun hits their leaves. Shown below is a before and after photo of some oregano that was heavily affected by the frost. I watered the foliage with a hose on low pressure, and the water temperature melted the ice without causing any damage to the plant. If the sun has already started to shine on affected plants, it is always a good idea to still mist/water the foliage to help reduce the chances of further damage.
Choose tough! If you live in an area that is known for experiencing heavy frosts, try and avoid planting frost-prone varieties.
Move pots and containers! Container gardens that can be moved and re-located under under-covered areas will prevent frost from settling on the foliage.
My plant is frost burnt; what do I do to fix it? Knowing when to prune.
When a plant is damaged by frost, there are usually two main symptoms. The first symptom is the most obvious, affected plants leaves turn black and begin to wilt. If the foliage is black and the main stems are still green, cut the plant back to the healthy green stems. If left un-pruned, plants are at risk from rot, fungal diseases, and stem dieback. Once cut back, if in a pot, move to a frost-protected position. Otherwise, if the plant is in a garden bed, make sure to cover the plant if another frost is expected. But in most situations, when the leaves turn jet-black, especially annual flowers and vegetables, it is not uncommon for the plant to eventually die.
The second symptom is more common on perennial plants with thick, robust foliage, such as Ficus and Syzygium. Affected plants will have their foliage will turn brown/copper. Pictured below is a Metrosideros bush which was burnt by the recent frost. In this case, I wouldn’t prune the affected foliage until the end of winter. The reason is that the affected foliage will act as a buffer for any future frosts and protect the healthy leaves hidden below.
See slider image below.
As you can see in the second photo, there is plenty of healthy leaves below the damaged foliage. This Metrosideros will make a complete recovery once pruned in the spring!
The last symptom is translucent foliage. These symptoms can be instantaneous, or it can take several days until the symptoms appear. Affected plants also start to wilt, and it is best to avoid pruning until the final frosts in late winter pass. Plants that are affected are likely to recover.
I hope that this guide to beating frost can be helpful to your adventures in your garden!
Until next time happy gardening!
By Bonnie-Marie Hibbs
Article Updated from the 2017 Orginal Post.