GARDENING; High cost of heavy frost.

It's been yet another week of anxious weather-watching.

Last weekend, the wind veered round to the chilling north-east and the weather changed from mild and damp to sharp and frosty.

Minus three seemed to be the average nightly temperature, but Monday night was a worrying minus six and there's no prospect of thaw until this weekend.

On Tuesday morning there was a light dusting of snow everywhere - not the fluffy snow which wraps the plants in a good insulating blanket, but that nasty, mean, thin stuff which comes from a clear sky and coats everything with a freezing crust.

Most things, even semi-hardy plants, aren't knocked back by the odd night of sub-zero temperatures, but when it goes on night after night, things really start to suffer.

Mind you, it was beautiful. We woke every morning to a garden of filigree lace and spun sugar, magical as a fairy kingdom.

YOU can see why magazine articles on winter gardening are always illustrated by a photograph of a garden made glamorous by a coating of hoar frost.

It looks far more romantic than the dripping, sodden browns and blacks of the usual winter landscape here.

But give me the mud any day - at least my plants won't suffer.

I tried to console myself by thinking that at least this frost is seasonal. Last winter was exceptionally mild. Tender spring growth appeared early, only to be mugged by a wicked night of frost, which blackened and crisped foliage, rhododendron buds, magnolia flowers, everything.

One of nature's cruel practical jokes. May we be spared it this year!

The frost has its consolations, though. The seeds I sowed recently will have had their dormancy broken by a good freeze.

These were mostly of herbaceous perennials, oriental poppies, primula, anemones, peonies and many more.

Hungry mice permitting, they should germinate like cress now. Checking the seed pots after a freeze is one of the rare joys of winter.

You probably think I'm making a fuss about a wee bit of frost, which is not uncommon in Scotland.

You're right, but you have to remember that I'm not a practical gardener.

I'm more of a crazy optimist. This is a mild garden anyway. It sits high on a south facing slope and the burn which flows through the garden often carries frost away - cold air flowing like water.

Around the house are borders, which are even warmer.

They have what we call a microclimate, their own wee climate separate from conditions in the rest of the garden.

NOW, I love to garden on the edge, to push my plant-growing to the absolute limit of possibility.

So these warm borders are crammed with tender plants normally only grown in Cornwall, the extreme south of England or Scotland's amazing west coastal gardens.

There are fabulous gingers from the temperate forests of the Himalayas, wild red- hot pokers from the South African veldt, giant cranebills from Madeira and, on the wall, a fig, which one day I hope to see heavy with luscious fruit.

And, above all, there is echium x wildprettii, a plant which I long to succeed with.

The Canary Island relative of our native vipers' bugloss is a splendid feature of mild gardens, like wonderful Logan Botanics, where it seeds around merrily.

It's a biennial, dying after flowering, but if my other `tenders' are anything to go by, the second generation of self-sown plants are hardier than their parents.

In its second summer, it throws out towering spires, seven foot tall, of showy mauve flowers, a dazzling floral fireworks display.

I've already failed several times with this showy giant.

But my seedlings, squeaked through last winter and I'm determined not to lose them now, as they'll flower next summer.

It's in my warmest border, which spend the winter under a cage of green netting as additional frost protection.

It also enjoys poll position, planted against a chimney wall on the other side of which is a wood-burning stove.

Each frosty morning I visit my echiums, staring long and hard trying to decide whether the all- important growing tip has been damaged or not, willing them to pull through.

Gardening is full of these highs, cancelling out the disappointment of many lows. I hope my echiums are one of the highs.

PLANT OF THE WEEK

TIBOUCHINA

SEMI-DECANDRA

THIS shrubby conservatory or house plant used to be as rare as hens' teeth, but is now quite common in garden centres.

Hailing from temperate South America, it has handsome ribbed leaves, red buds and wonderful violet flowers full 3inches across.

Treat it like a fuchsia, pinching the tips encouraging branching. In a warm light window it flowers all winter, but repot into a clap pot as it tends to be top-heavy.

An excellent Christmas present.