Canberra has its own unique heat. I (mostly) grew up in Queensland, but stepping into my first Canberra summer was like opening the oven door. The air was so hot and dry my eyebrows seemed to shrivel.
I blamed the car parks. I still do. Canberra's vast car parks breathe out heat even at 2am.
Car parks can have air conditioning units too. They're called ''leaves''. A leaf-filled suburb is a cooler one. Leaves create shade, but even more importantly in the dry air of Canberra, leaves transpire moisture, cooling the air. I'd love to see standard concrete car parks outlawed. Give them green roofs, though not necessarily soil covered ones. Soil is heavy. Damp soil is even heavier. But plants like Tillandsia don't need soil, just open air, sunlight, and some glue to stop them sliding off the wall or roof.
There are hundreds of varieties of Tillandsia, in a myriad of shapes and colours, but all have neat rosette leaves that capture the moisture they need from the air. If humanity ever travels to Alpha Centaurus we might do so with ''green walls'' of Tillandsia - five metres of leaf area can produce enough oxygen for one person, though if the astronauts don't have green thumbs, a bit of leeway might be a good idea.
Tillandsia can often be found glued onto decorative rocks at garden centres or gift shops. Our home had half a dozen green- and red-topped ''pet rocks'' for many years. All they needed was a splash under the tap every week or two, as our living room was a bit dry for them, unless I'd been simmering soup for a couple of hours. A nearby simmering stock pot and a sunny spot was all the Tillandsias needed to thrive.
If you'd prefer native plants above your car park, cover them with salt bush, or Sturt's Desert Pea - a gorgeous ground cover with vivid red flowers which could well replace the water-loving grass that covers Parliament House.
Sturt's Desert Pea are tricky to grow - seed needs to be soaked in hot water overnight, then planted where they will grow. Seedlings almost always die if transplanted, and will promptly decease if overwatered or the soil isn't perfectly drained. This should not be a problem above Parliament House.
Native rock orchids (Thelychiton, formerly called Dendrobium) are another dazzler that grow on hot rocks with no soil, as long as the wallabies and goats can't reach them. Wallabies and goats are also rarely seen on Parliament House.
An even better way to cure the feral car park problem may be to use them to harvest rainwater or even condensation. A roof, or even strips of roof, that drain rainwater into gardens, would help to keep Canberra cool and green, lower water consumption, improve the general feeling of ''this is a lovely city to live in'' as well as protecting cars against hail storms.
Any addition to CNLP (Canberra's Net Leaf Population) is a good thing. Everyone can add to it. Trees are an especially good addition to the CNLP if they shade a hot driveway, a blazing footpath and even some of the ''could fry an egg on it'' road.
The ideal street tree doesn't fall over when its branches get sodden, or drop large branches, invade your water pipes and house foundations or stain the roof of any car below it (which rules out English mulberries) or attract fruit fly. It also needs to thrive on neglect, and live for at least 100 years and preferably longer - trees to plant for generations to come, not just the next few years.
Eucalyptus preissiana might fit the bill - they don't grow too tall, have gold blooms and large gumnuts, but are edible only for possums and don't really give a truly shady canopy, though eucalypts also cool the air as moisture evaporates from their leaves. I'd go for kurrajongs if you want a native tree - dense shade, hardy, and an excellent forage tree to feed your stock in a drought if you happen to have a backyard farm. It will give you the material to make your own string or fishing nets, should the desire suddenly strike you.
Pin oaks and red oaks are the most spectacular ''public'' tree in Canberra, with flagrant colour in autumn, but for a truly deep canopy the English oak is magnificent. I planted an English oak as a memorial tree for a loved one 35 years ago, and for the past 15 years it's been the perfect shade for summer lunches, layer after layer of branches shielding us from summer sun and cooling the air below. Its leaves also provide the winter mulch for young trees as its massive roots bring up nutrients deep in the soil. Even in this bushfire summer it hasn't wilted (yet). It is, however, enormous, about half the size of a modern backyard.
This has been a ''survivors'' summer, a test of what trees are still green here. The native Melias are flourishing; the date palms actually flowered and set fruit, though I suspect the possums will soon discover the young dates; the loquat, olives and chestnut trees haven't noticed the drought yet, and the apples, almonds, pomegranates, pecan and pears keep putting out new leaves and the possums keep eating them. Loquats' early fruit can attract fruit fly, unless you have enough possums and fruit bats to eat them all (we do). Apple and pears attract fruit fly too unless you plant varieties that ripen in winter, when Canberra fruit flies have been zapped by the frost.
A drought may seem like an odd time to urge everyone to plant trees. But this is when we see how much they are needed, not just for their shade but to add the desperately needed moisture to the air. I wish I had planted 100 English oaks 36 years ago, and as soon as we have enough water, will be planting at least 100 gorgeous kurrajongs.
And could some politician, please, outlaw nude car parks, and have them covered decently in cooling greenery or water harvesting?
This week I am:
- Trying to peer into the thicket of prickly date branches to see what is happening to the dates.
- Hoping that the dahlias that have finally poked up shoots will survive being nibbled by the horde of wallabies feeding here who've fled from areas burnt by bushfire.
- Discovering that wallabies who may have come from the burned areas of rainforest like to eat tree fern leaves - and have taught our wallabies bad habits. Or useful ones, if you are a wallaby.
- For the first time in many decades, not pouring through at least half a dozen seed catalogues to order new varieties of leeks, red cabbages, onions, winter lettuce and other greens to see us from autumn through spring - not until we get some rain.
- Glad that the perennial chicory, leeks, asparagus, capsicum, rhubarb and other hardy veg have survived despite no watering from me and only two short episodes of wetness from the sky in the past five months.
- Still addicted to the Captains Flat radar site and the weather forecast, hoping that the rain predicted for this weekend might actually fall from a sky grey with clouds, not smoke.
