“The third day comes a frost, a killing frost.”
- Shakespeare
The first big frost of the season struck last Friday. The temperature got down to minus six at Thistlebrook, which isn’t quite as cold as the two black frosts of July 2007, but is still a pretty heavy freeze for this part of the world. This morning I toured the garden to assess the damage. The results aren’t pretty.
Nasturtiums, plants I like to use in the vegie patch as a companion, are a complete wipe out and now resemble a slimy ooze with the scent of rotten mustard. But I expected that. They’re tender annuals, and plenty of seed was set for next summer. The agapanthus always get badly damaged in a decent freeze, but I expected that too. The same goes for the cannas, which at least have enough dignity to turn the colour of a brown lunch bag, rather than becoming a pile of slime. They bounce back, and would have been cut down in the next month or two anyway.
A couple of plants confirmed my suspicions. All the citrus – a Valencia orange, an Imperial mandarin and a blood orange – fared poorly, and are now curled and crispy. The foliage on the Eureka lemon is fine, but the ripening fruit has turned to mush. I took a calculated risk with all of these plants, and considering they were covered on the coldest nights I’ve decided that most aren’t hardy enough to perform well and will most likely be replaced with something deciduous. A calamondin planted just a couple of months ago in the vegie garden looks fine, other than a slight darkening of the foliage.
Some of the grevilleas have been disappointing. My ‘Robyn Gordon’ did fine last year but this winter looks like it’s been sandblasted, and a recently planted hedge of Grevillea rhyolitica appears to be totally cactus. What annoys me is that this species was sold to me by the grower with the assurance that it would handle hard frosts. In my experience, it doesn’t.
That’s just some of the casualties, but what about the survivors. Most of my perennials and ornamental grasses are made for last week’s weather and breezed through unscathed. Ditto for all but one salvia. A hedge of Photinia ‘Camilvy’ is unperturbed, as is a Ceanothus ‘Blue Pacific’ hedge planted in one of the frostiest parts of the garden. Camellias continually prove their worth, and despite having very full buds, they too have come through totally unaffected. Anything deciduous, be it a tree or a shrub, has performed as beautifully as expected, and the couple of conifers that have found a place in the garden are a picture of rude health.
The lesson of this little tour through my frost ravaged garden is straightforward enough in principle: to save time and money, it’s best to choose fully hardy plants. Hardiness is one of those horticultural terms that constantly gets misapplied as a measure of general toughness, but I was taught that it actually refers to a plant’s ability to withstand subzero temperatures. Thus, a plant can be tender (disliking any frost), half-hardy (taking light frost only) or fully hardy. At my place temperatures can get down to minus 10, real brass monkey weather. Tender and half-hardy plants just don’t cut it.
In other words, I need to be more disciplined in my plant choices. This is tough medicine for someone who loves to grow stuff, but I’ve got no desire to see the garden become a hospital ward for ailing plants. If they can’t cut it, they have to go.
So for the next month or two, I’ll try to be ruthless. The casualties will be summarily grubbed out and given a rebirth as shredded mulch, and a selection of fully hardy plants will take their place. On the list are more temperate fruit trees (I can always find a spot for another heritage apple), and more deciduous shrubs. For years I’ve been a reluctant admirer of conifers, appreciating their toughness but finding them a bit stiff. They tend to be bone hardy though, so if a spot comes up, a conifer or two might get a look in as well.
Even writing this I’m finding it hard to stay disciplined. So many species, so little time! But the alternative – plants that get badly frosted every winter – leaves me…cold. The old mantra of the right plant for the right place rings truer than ever.
First published in the Toowoomba Chronicle 20th June 2009. Photo by John Arnold.
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We had a late snow this year (for us in Northern CA) luckily we had our garden covered, and other plants we were able to take inside when we heard it on the news that a quick storm front was blowing in :(