Asked to name her favourite garden in the South causes her to pause, flick a crumb of earth back into place and announce: "It would have to be Altamont, yes Altamont." As with Mount Stewart, Altamont, well hidden in the Co Carlow countryside, is associated with one individual, the legendary Corona North, who died last year having spent her life continuing the work of her father, an accomplished plantsman, Fielding Lecky Watson. On his death in 1943, Corona, then newly married, returned home, and devoted her energies to Altamont.
Snowdrops are already out at Sandford Road. Dillon has about 50 varieties of them. "But there are about 200. People who are really red hot would have them all. If I could grow only one snowdrop, it would be Galanthus `S. Arnott'." The secret is to transplant them in growth, either in flower or just after, and then they settle in immediately. As she says, they do a lot of growing between flowering and dying down. Green is the dominant winter colour of the Dillon garden; the pyramid box and yew currently enjoy centre stage. It is also pleasing to hear her praise the virtues of an ordinary worker plant such as Viburnumtinus. But there are flashes of colour. Delighted by the response to the bright red provided by her rare quince, tree peonies, evergreen ferns, she mentions another rare fern which has yet to make its appearance, but she is less pleased to be asked about herself.
Although by now resident in Ireland for almost 30 years and certainly a national institution in Irish horticulture, the nervy, flamboyant Dillon appears quite paranoid about being an outsider and blames it on her accent. The eldest of three and the only girl, she is a Scot and grew up in Perthshire. Her family belong to the Scottish peerage and she is, by right, the Hon Mrs Val Dillon. An ancestor, Sir William Rollo, was beheaded in 1645 by Cromwell's men. Make no mistake about it, the accent is upper class and intensified by having attended Heathfield school near Ascot.
There she says, "gels" learnt more about being prepared for "good" marriages than about academic pursuits. "I began gardening as a child. I was always interested. I gardened at school. It was always the thing I most loved. It was also a good way of getting out of sport, which I hated." She was born into privilege and openly says as much. But she also stresses she wanted to get out and fend for herself.
Having left school at 16, she went to London and tried a number of jobs. "I always wanted to be a journalist," she says. She has also resented that after school she did not go to university, a place reserved for her brothers. "It's a thing I've always been chippy about. I wanted to go. I did when I was 23 or 24; I decided to study Russian but . . . " she shrugs and explains that she realised then that "it wasn't really for me" and left after six weeks.
An impulsive curious character, she is interested in fiction and has two copies of Annie Proulx's short stories. "One was sent to me by a friend who said I simply had to read them, but I had already bought the book. I'm also reading The Hours by an American, Michael Cunningham. It's good, isn't it?" On a round library table in the yellow drawing-room are a number of gardening books. She says, "when I first started out I read about a million", and she remains fascinated. The photographs in the books seem to draw her, just as many of the pictures and prints on the walls are of plants, such as a print dated 1770 of a group of those most pleasing of hybrids, auriculas. "A very popular plant in 18th-century Dublin." Botanical prints, both antique and modern, feature throughout the house.
Although the Dillon home, with its yellow and terracotta walls and plain furniture, is elegant and uncluttered, it has an air of practicality. On entering the drawing-room in daylight, it requires some effort to look anywhere other than at the view of the garden. Seen from a height, it rises from a patio generously populated by pots and containers, and seems to be guarded at the top step by a pair of terracotta sphinxes, one of which is shouded with ivy. The sun shines in, and the lawn glows. My throat has tightened with a form of rarified envy. The pair have created a formal garden which is also romantic. Val Dillon breaks the silence. "It's amazing the way the winter sunshine always shows up how dirty the windows are," he observes thoughtfully.
But back to the Dillon youth, or rather Rollo as she was then. Among her various jobs was one dealing in antiques. This venture began when she won some money, "£180", on a horse race. With that sum, she set herself up as a dealer. Val, her husband-to-be, was already dealing. "I heard about him before I actually met him. It was a case of there being some sale or other and when I arrived I would always be told `Val Dillon's already been here' and then, after a while, when I was being told about a sale coming up, I often heard, `you'd better hurry before Val Dillon gets here and snaps all the good stuff up'."
They finally met up in 1969, and married within the year. For a while they ran an antiques business in London but knew they would move elsewhere. A number of possibilities were considered, such as Scotland. But they came to Dublin and fell in love with this plain, late-Georgian house which was built in 1830 and had an old garden. It was the right home for them. The Edwardian plant collector, Dr Augustine Henry (1857-1930) after whom Rhododendron augustinii is named, once lived next door. His spirit must be well pleased by the neighbouring garden. Having spent some years working in China, Henry sent his first collection of 1,000 Chinese plants to Kew gardens and became an authority of Asian flora. Dillon, who has also travelled to New Zealand, the Andes, Patagonia, Nepal, the US and throughout Europe in pursuit of plants - "although there was a time when I didn't travel for 15 years; I was terrified of flying. But then I realised `here, hold on a minute' " - could not have hoped for a kindlier ghost.
There is a round, formal pond with a fountain, and a number of trees. Along with New Zealand daisies, grown for their silver foliage, is the most beautiful of ground cover Senecio candidans from Patagonia. A wonderful tree peony lives beside the Alpine House and waits for April. Lapageria rosea, the national flower of Chile, thrives in the nearby greenhouse, along with a number of plants that are natives of South Africa and elsewhere. All is calm order, chaos does not figure in the Dillon garden. Even at the height of summer, the mood is of abundance, not confusion.
No gardener is ever fully satisfied, and Dillon is surely among the least complacent. For all the glories of her kingdom, it is all contained on just under an acre of walled town garden. If space was not a concern, what would she do? "I'd plant avenues. I adore oak and I'd plant avenues and avenues of oak."
The Dillon Garden at 45 Sandford Road, Ranelagh, Dublin 6, opens daily in March, July and August between 2 p.m. and 6 p.m., and in April, May, June and September, Sundays only, between 2 p.m. and 6 p.m.
