Journal of the Australian Native Plants Society Canberra region (Inc)
Killing Frosts of Winter in Canberra 2025
By Ros and Ben Walcott
Aug, 2025
There are many great things about a Canberra winter, sunny days, blue skies and cool air to breathe, but killing frosts in the garden are not welcome. This year we endured five nights in a row where the temperatures fell below minus 5 degrees between June 26-30. The last time this degree of frost occurred for this number of nights was in 1965, 60 years ago. We also recorded minus 7.6 degrees on Saturday, June 21 – the last time that it was colder than that in Canberra was in 1957 (Weatherzone). Our garden has many plants that could be considered experimental in our climate. We have been spoiled by mild winters over the last few years which have allowed these tender plants to make it through our winters, but the winter of 2025 proved to be their comeuppance
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Hardenbergia violacea ‘Meema’ Corymbia ‘Summer Red’ Thomasia grandiflora Alyogyne huegelii ‘Eastcoast Gem’
We have lost many plants – even some ‘protected’ in the shadehouse or supposedly ‘protected’ by overhead foliage. Some plants well-established on warm walls have succumbed this year, for example, Hardenbergia violacea ‘Meema’. Some of our ‘Meema’s have survived while others are comprehensively dead. The following list is of plants we have probably lost.
Acacia inaquilatera – Kanji Bush, Baderi, Fire Wattle – planted May 2025 in a pot, in the shadehouse
Alyogyne huegelii ‘Eastcoast Gem’ – new planting under protection January 2025
Calocephalus citreus – Lemon Beauty Heads – new planting January 2025, disappeared
Cassinia uncata – Sticky Cassinia – planted November 2023
Coronidium ‘Sunny Side Up’ – planted under overhead cover, February 2025
Corymbia ’Summer Red’ – planted March 2024 in a pot and moved to the garden May 2025
Eucalyptus conferruminata – Bald Island Marlock, Bushy Yate – planted in a pot in the shadehouse December 2024
Eucalyptus globulus ssp. maidenii – Maiden’s Gum – planted October 2006, long established, but now one half completely browned off
Gossypium ‘Flirtatious’ – planted in a pot November 2020, long established, but now completely browned off
Hakea platysperma – Cricket Ball Hakea – planted in a pot February 2025
Pultanaea altissima – planted February 2025
Thomasia grandiflora – planted May 2022, well established, but we lost the Banksia that protected this plant
Xeronidium ‘Unity’ – planted February 2025
Syzygium australe Leptospermum ‘Pagent’
We also have many plants that are badly burned by frost which may or may not survive listed below. You do have to be very patient in spring and look carefully for signs of life under the depressing brown foliage. Syzygium australe has been blasted by the frost again this winter, but it has always come back from complete disaster – fingers crossed. I find that some plants come through the winter looking green and hopeful then often die at the very end of winter in the last week of August. They look fine until they don’t.
Asplenium australasicum – Bird’s Nest Fern – planted in a pot in September 2023 – under protection, but very browned off
Blechnum medium (was Doodia media) Planted, under overhead protection, October 2020
Blechnum neohollandicum (was Doodia aspera) Planted, under protection, October 2020
Grevillea ‘Lemon Daze’ Planted September 2019
Hardenbergia violacea ‘Meema’ Planted December 2022 on a warm wall – one is completely dead and the other not
Hibiscus ‘Aussie Delight’ Planted March 2021, in a pot, under cover
Hibiscus geranioides Planted October 2015, in a pot, under cover
Hibiscus heterophyllus pink Planted November 2019, in a pot, under cover
Hibiscus ‘Ian’s Gold’ Planted October 2021, in a pot, under cover – moved to garden January 2024 – bad timing
Paraserianthes lophantha – Cape Leeuwin Wattle or Plume Albizia Planted January 2021
Rhododendron lochiae – Planted in a pot, under protection in February 2020
Syzygium australe Planted December 2008, drops browned leaves every winter, but so far has resurrected itself every spring
For those of you who do not have to worry about frost, it is worth remembering that it is essential for those of us who do to have correct frost information on our plant labels. ‘Frost tolerant’ means that you can sometimes get away with planting these species against a warm wall, in a warm spot, or under overhead foliage protection. But to plant with confidence you need ‘frost hardy’ on the label. Many labels have no frost information at all. It is incredibly useful to have degrees of frost hardiness noted. In Olde and Marriott’s 3-volume The Grevillea Book they note frost tolerance and native rainfall averages when known. Some labels will include degrees of frost hardiness and this is to be encouraged.
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