Dunbeath Castle is built on a steep, narrow promontory of rock, surrounded on three sides by the sea. In terms of military defence, the situation is ideal, but by any other measure this is as inhospitable a place as Wales on Sunday. So the visual shock, when you open the door into Dunbeath's secret, walled garden is all the greater: roses, delphiniums, snapdragons, honeysuckle, brilliant annuals, fuchsias and agapanthus pack pell-mell into the short growing season which is all the time the terrain allows.
Dunbeath's gardener, James Campbell, has worked here for 20 years. Didn't he ever get frustrated by frosts in late May and early September, sea fogs, gales from the north-east and from the south-west, all of which are standard fare at Dunbeath? "I was born here," he said, simply. He has never known any other way of gardening. "I like the atmosphere of the place. I'm not a hustle and bustle person."
The weather, he concedes, can be "very brutal" and this year has not been an easy one. There has been very little sun and the annuals he set out have been sulking because of it. His Livingstone daisies gave up the ghost altogether. However, the double herbaceous borders that run down the centre of the garden are flourishing, with wonderful swathes of agapanthus edging the central roundel.
The garden is divided into eight plots, four either side of the great double borders. It's still a productive garden, as it was meant to be when the walls were first thrown up some time around 1800. There are cabbages, peas, onions, potatoes, masses of soft fruit, all edged with annuals. Globe artichokes thrive, which is surprising. So does the Moroccan broom, Cytisus battandieri, which is carefully tied in against the wall. Like the one-time soldiers on the ramparts of the castle nearby, it has learnt how foolhardy it is to stick your head above the wall.
The garden slopes gently down to the sea, which is mercifully out of view, until you climb up one of the sets of stone steps which lead to bastion look-outs in the corners of the walls. At the top of the slope is a long range of glasshouses with peaches and figs trained against the back wall. "Always the first job after Christmas," said Mr Campbell. "Untie the fig. Lay down its branches. Scrub and whitewash the wall. Then tie it all up again." If I were him, I'd be spinning out the inside jobs until well into April.
They say in Caithness that the best growing only comes after the turn of the year. After the longest day, the plants go like the clappers before they are cut down by the first frost. At Candacraig in Aberdeenshire, in the quiet, unvisited valley of the Don, the growing season is slightly longer, and Liz Young, who bought the garden 12 years ago, says that June is perhaps her favourite month, with Asiatic primulas flowering fit to burst and huge swathes of sky blue meconopsis filling the beds. She even succeeds with the rare, red-flowered Meconopsis punicea, which caused such a sensation at Chelsea when it was shown on the Alpine Garden Society's stand.
Candacraig is a walled garden, too, built about 1820. It belonged to the big house next door until, in the Eighties, the estate had to be split up. Liz Young and her husband, Harry, with no previous professional experience of gardening, decided "on impulse" to buy the walled garden, which would otherwise have been covered with new houses.
Harry Young, by his own admission, is not a gardener. He looks after the paths. Liz does everything else. I dared not think how many hours she worked in a day. "Oh, I'm quite stubborn," she says. She must also have a cast-iron back. The place is richly romantic, spilling with great mounds of geranium, globe thistle, shaggy-petalled inula, with special beds for meconopsis and primulas set behind the great formal double borders that sweep through both levels of the garden. It's an eloquent tribute to the virtues of stubbornness. The garden at Bolfracks, near Aberfeldy in Perthshire, overlooks the Tay, a much more familiar river to most tourists than the Don. Tourism in Scotland is built around neat packages: the whisky trail, the castle trail, Speyside, Deeside, Tayside (though no Donside). How long before we are offered the Safeway trail? Their supermarkets featured prominently on the outskirts of many towns I went to last week. Meanwhile, high streets staggered on the wrong side of viability, blind windows boarded up behind decaying, though handsome, facades.
Bolfracks tells you immediately that it is a much-loved garden, impervious, quite rightly, to fashion. It has a quiet peace and self confidence, with the planting still singing of the Fifties: cherries, acers, berberis, rhododendrons. It is beautifully gardened, though mildew was playing sad havoc with the phlox in the borders.
The lawns, sheltering inside compartments made by old shrub roses, were diagonally cross-mown, which, given the slope they are on, is not a job to take on lightly. At the top of a path that winds upwards alongside a small stream is a twig-house, where I could happily have spent the rest of the week looking at the clouds sailing over the Grampians.
If you are planning a trip to Scotland, forget the brown-signed tourist trails. Buy a copy of Gardens of Scotland (pounds 2.50), published by Scotland's Gardens Scheme, and take yourself off-piste.
The garden at Dunbeath Castle, Dunbeath, Caithness is open tomorrow (2-6pm) Admission pounds 1.50. Candacraig gardens and nursery, on the A944 at Strathdon, Aberdeenshire, are open daily until the end of September (Mon to Fri 10am-5pm, Sat and Sun 2pm-6pm) Admission pounds 1. The nursery does mail order - send two first class stamps for a plant list. Bolfracks, Aberfeldy, Perthshire is open daily (10am-6pm) until the end of October. Admission pounds 2.