Garden guru: Endless summer

The giant granadilla - in flower now - does a spectacular impression of a man-eating triffid. Photo / Supplied

Winter - what's that?

If flowers had teeth, the giant granadilla would eat you up before breakfast.

This passion vine (Passiflora quadrangularis) is a monster in every sense of the word. Its big, leathery leaves range far and wide and it needs a sizeable and sturdy climbing frame to launch itself at.

With good soil and a generous feed, passion flowers, despite their delicate beauty, are remarkably tough and great vines for a seaside location - but it's a slightly unnerving sight to catch any of them reaching down at you now, with sea-anemone jaws gaping as we head into winter.

Winter, after all, is surely the domain of subtlety and restraint. In the bareness of the garden, shouldn't we be scratching about to find something interesting - a bit of polished bark, or a flurry of delicate winter bulbs poking out tentatively from the leaf litter? In cold gardens, maybe, but in the many places where frost keeps its distance, there's nothing to stop you partying hard with monstrous plants which defy the cooling weather.

It's a pain, but the best subtropical beauties can be a bit tricky to get hold of from mainstream outlets - the trouble is that they are just too muscular to fit into a tidy little retail stand. But any garden centre worth its salt will go out of its way to source rare but delicious plants and, if you keep your eye out driving about the suburbs, there's always an opportunity to slam on the brakes and lean over a wall with your secateurs.

Despite their glamour, many subtropicals are surprisingly easy to propagate from cuttings. That's how I acquired my biggest plant surprise - the Mexican daisy tree, or Montanoa - which was spotted lurking in the gloom of an overgrown villa garden.

I snaffled it up for its handsome leaves and it was only a year later, when my cutting had rooted and bushed, that it thanked me by sending out great sprays of pure white flowers sparkling against a deep-blue June sky. Icing on a sizeable cake.

At 3m high and almost as much across, you might think that this is too big for an average garden, but Montanoa is basically just a big perennial. The wood is soft and responds best to a heavy prune at the end of winter. Its feet are nimble, so it can be squeezed into a comparatively narrow place and allowed to arch over the fence, where it will likely put on its best performance for the neighbours.

Senecio grandifolius - now annoyingly renamed - is a similar shrubby show-off with handsome leaves, but this time the flowers are more contained - great fat heads which look like someone has tied cauliflowers on to the bush and sprayed them yellow.

Again, this is an easy plant to increase from cuttings and it can get a bit tired and ungainly after a few years unless you prune and feed annually, but otherwise this is a great fence-hider and comment-grabber.

Many winter highlights started flowering months ago, but rather than being hangers-on, they come into their own now that the soil is moist and temperatures are cooler.

With their long eyelashed flowers and velvety leaves, tibouchinias are truly sumptuous plants and there are lots of interesting varieties beyond the violet/purple version if you know where to look.

Some are large in pink or white, while others pile up masses of smaller flowers to create hydrangea-like cones of flower, but all have those fantastically pleated leaves again, so they are not just a one-trick pony.

Hibiscus, too, have arguably their finest flowering in winter rather than in late summer, which is the traditional season we associate them with.

The secret is to give them enough light and shelter and to feed them regularly to encourage a prolonged performance.

Turbocharged plants work best in a muscular setting. If you can provide a backdrop of architectural natives like flax and cordyline - and throw in traditional winter flowers like proteas, leucadendrons, aloes and camellias - they won't look out of place.

Dead grasses and bare soil have their place in the winter garden, but for now I'd rather step out of the back door feeling that I've arrived at a carnival rather than a funeral.