Dare to dream the impossible dream

Our garden doesn't have any frost-free spots, or much sun, in our narrow valley. But the lime tree flourished, not even turning a leaf in drought or cold when the lemon trees struggled to survive. I'm about to give a kaffir lime to a neighbour who loves using the leaves in her cooking (and we love eating what she cooks). My advice these days? Just bung it in.

Most gardeners sensibly stick to the plants that grow well in their region. Other gardeners get a wild gleam in their eye and plant the impossible, cosseting their plants to see what treasures they can grow.

Canberra resident Cheryl Harriss has just sent me a photo of the gorgeous jacaranda her husband Gordon has grown. It's covered in blue flowers, considerably later blooming than the jacarandas that lined the streets when I grew up in Brisbane. They flowered at exam time, leading to the phrase uttered every time the trees covered the footpath with their blue carpet: "What you don't know when the jacarandas bloom, you'll never know".

The photo shows a jacaranda blooming over paving. Paving reflects heat and retains it overnight - it's like a kind of electric blanket for jacarandas. Paving, warm sunny brick or stone walls or a sheltered courtyard are all excellent for coaxing plants that expect to be grown in a warm temperate or subtropical climate, instead of Canberra's "Maybe it will snow today, or maybe we'll have a heatwave".

Steep, north or north-east facing banks are also great for plants that hate frost - our kaffir lime is planted on a north-east facing slope . Frost "flows" a bit like water - well no it doesn't, but the analogy shows you how to cope with it. I can grow plants on that sunny bank that won't survive or fruit elsewhere, like the date palm that was not supposed to fruit for at least another 15 years, and not without a pollinator. At least we know our trees is a female.

A surprising number of plants will thrive with a lot of coaxing in their early years. Plant a couple of compatible varieties of avocado side by side to pollinate each other. Feed and mulch and water them exceptionally well over summer, then cover them in winter with one of those polypipe greenhouses covered in plastic. Avocadoes get more cold and heat hard as their roots get deeper - so do most long-lived plants - and after five years or so you should have fruit, plus trees that don't need shelter any more, though you'll need to keep up the tucker, mulch and watering.

The true trick to growing far more than your neighbours is to hunt out catalogues and look for the magic words "cold hardy" and "drought hardy", whether it's roses, fruit trees or long-blooming perennials. It is also worthwhile studying labels for "need good drainage" in case your soil is compacted clay and shale, or "full sun" if all you have is a shady patio and an oak tree that covers most of your backyard.

If I'd been a proper, respectable, plant-more-dahlias, six-roses kind of gardener, we'd never have had bananas growing (they don't taste of much) or lychees, the vast purple bougainvillea covering a pittosporum, or the heliotrope that smells of cherry pie.

There is so much a gardener who is prepared to do a little cosseting can grow in this region, even without a glasshouse or turning the spare room into an indoor hydroponics farm - jacarandas, of course, or citrons, tangelos, native lemon myrtle, Tahitian limes, the new cold-tolerant mandevilleas that have almost too much paradisical perfume, the newly available (sometimes) cold-tolerant mini bananas, macadamia trees, cork oaks, deeply fragrant and heat-loving Greek oregano, shade-tolerant roses on a gloomy veranda, maple sugar trees (wait a decade so to harvest) or banana passionfruit with their gaudy giant pink blooms and bright yellow fruit against a warm sheltered wall...

I could go on for pages, but I have promised (again) that I won't buy any more trees or shrubs this year, and am trying to keep away from temptation. But if you feel like a plant to cosset, or to boast about, or simply to glory is the gentle blue of jacaranda blooms above you, this is the perfect time to hunt them out, and plant while the weather is gentle.