According to a recent article in New Scientist, sitting under an umbrella will make you one degree cooler. That umbrella may block out the glare, or reduce sunburn, but keep you cool? No way.
The urban planning buzz now is about creating "shade zones" in our cities, which is a tactful way of saying that unless we start cooling our cities now, you, the dog and your flower garden may collapse from heat exhaustion.
The most popular solution for cooling is to plant more trees, and this is the perfect time of year to choose and plant them, as nurseries have just begun their end-of-season sales.
A suburb with well-watered trees will be 8-18 degrees cooler than it would be without trees.
There's only one problem: modern town planning leaves too little room for big trees. The latest sustainable building design awards all seem created for some neat shrubbery, not for trees.
Some modern suburbs don't even have footpaths big enough for small trees, much less the glorious giant blue gums, fabulous big red box (Eucalyptus polyanthemos), kurrajongs, elms, oaks and Lombardy poplars that once made Canberra a green city.
House blocks are smaller; the houses have become massive, and backyards have become tiny courtyards with front yards that are mostly paving or lawn with a few shrubs.
Modern Canberra needs trees that will fit in small gardens but still give good shade. So I had a browse in a couple of magazines to get some ideas that weren't based on the plants in our garden, muttered to myself, then went online. Then I muttered even more.
Every one of the dozen or so sources I looked at had the same top three trees to shade small spaces - and none of those three would be effective.
The most popular was dwarf magnolia grandiflora 'Little Gem'. I tried to find a polite response to this, but can only say: are they crazy?
Magnolia grandiflora 'Little Gem' are gorgeous trees, neat growers with glossy leaves and brilliant white blooms, but their branches aren't wide enough to shade a King Charles spaniel.
Red dwarf Japanese maples were another top suggestion. I adore them - one grows in front of our house. But it is about 25 years old and the foliage is still so thin that an egg could be fried on a hot rock underneath it in midsummer. Japanese maples give beauty, but not shade.
The next popular suggestion was dwarf crepe myrtle.
We grow those, too, and I wish I had another half dozen, as they give the most vibrant fuchsia-coloured flowers for months. They are fabulous, but you'd need to hug the trunk to get any shade.
So what small trees do give dense shade, with wide enough branches to picnic underneath?
My first choice would be orange trees, with the lower branches pruned so that the top is a neat umbrella shape of thick green glossy leaves, with glowing fruit all winter. No other citrus will work for this - mandarins are too lanky, Tahitian limes, lemons and cumquats are too bushy. It must be an orange tree, and an extremely well fed one, as a hungry orange tree looks dismal. You also do need to do that pruning to remove the lower branches that would prevent you placing a garden table under them.
Second choice is one of the small but spreading kinds of crab apples, like the pink/white-flowered Japanese crab apple, (Malus floribunda) or Bechtel's Crabapple (Malus ioensis 'Plena') with large, rose-like pink double flowers in late spring.
There are dozens of other crabs just a suitable, but do check their shape, as some crab apples have an open habit. I make my favourite crab (species unknown) even shadier by growing the rambling Dorothy Perkins rose up its trunk and through the branches. This means we get flowers twice a year, and the shade is excellent. Climbing Albertine is another excellent rambler to grow up your crab apples to make them shadier.
Crab apples tend to have discreet roots, don't need pruning, and survive neglect and droughts.
The fabulous Aussie native macadamia is rarely grown in backyards, possibly because few people realise that they tolerate our cold winters well.
There are at least four dwarf macadamias that are reasonably common in garden centres. The best for shade is probably Integrifolia 'Daddow', which has a spreading, dense-leafed habit and responds well to being pruned. If you are worried about root spread, put in soil barriers about two metres square out from the trunk when you plant the tree, or plant within a large metal barrel with the bottom cut out. The roots will go down instead of up.
Some of the best shade for a house, garden or suburb with limited planting space comes from dwarf varieties of otherwise massive columnar trees, like 'Mini Capital' ornamental pear, which also gets a prize for the best autumn foliage.
Plant a row of them and they will be both neat and elegant, conveniently dropping their leaves just when you want sunlight, and give you fabulous stripes of dense shade.
A row of 'column' trees also gives privacy without the sometimes claustrophobic feel of a tall hedge. Passers-by can see into your garden, but only if they stop and peer. Passengers in passing cars will be going too fast to get more than a glimpse of few daffodils.
Other good column trees include 'pencil pines', the slender conifers that are a bit too tidy for my taste. They are also evergreen, so you won't get winter sun but you don't have to rake leaves, either.
There is a lovely Aussie Syzygium lillypilly called 'Straight and Narrow' that describes its growth habit perfectly, and an 'Acmena' lillypilly called 'Sublime', which is only a slight exaggeration. Both look beautiful planted in a row.
Lemon-scented gums (Corymbia citriodora) are a bit big for small gardens, but superb shady street trees for narrow footpaths.
None of these give the dense shade of the larger eucalypts or the English oak, possibly the world's best shade tree but too massive except in very large gardens. Even the dwarf English oaks grow to three or four metres tall and wide, though they will do so very slowly. They'd suit our increasing small public spaces though, and their shade is superb.
But this is also a plea to town planners, architects and developers: if you want your design to be truly sustainable, leave space for trees, the kind that are wide enough to shade a garden table and six chairs. Go back to the old Canberra road system with trees down the centre of the highway, cooling the bitumen that contributes so much to our cities' heat... and start growing creeping figs up every concrete wall in Canberra, or let Creeping Boobialla cascade down from window boxes so Canberra looks green again, not shades of grey and glass.
