One of the nice things about my job is that I often get to bring a little bit of other people's gardens home with me - a special cutting, a bit of seed, a spare bulb or two. And so, when I visited Mary Simpson's garden in Foxrock the other day, I left with an infant alstroemeria, some fuchsia cuttings and the curious, goose-pimpled pods of the red, pea-flowered Hedysarum coronarium. I'd brought something else with me too: invisible, but a persistent reminder of my visit. For close to 24 hours, a powerful aroma clung to my thumb and forefinger where I had scrunched a leaf of Tulbaghia violacea. It was kind of oniony, kind of foxy, and wholly intoxicating, conjuring up Mary's handsome autumn garden and this indelible plant with its pretty pale-purple sprays oscillating over strappy foliage.
It was a smell that, unassociated with that elegant plant from South Africa - known also as Society Garlic - could only be described as a rude pong. But the magic of botany (for gardeners, anyway) is that it works its alchemy on the most mismatched of elements to make a stimulating thing. Mind you, the books say that the flowers are sweetly scented, but it's impossible to know; you can't approach them without brushing the leaves, which emit their odour at the slightest provocation. Even a light rain triggers wafts of skunky scent.
The Tulbaghia is just one of the many individuals presently performing in this little garden, where even now, as the shadows lengthen and the days become chill, the borders and beds are filled with layers upon layers of late-blooming plants. In the back garden, Michaelmas daisies with their melancholy, purple flowers cast a dull glow. The earliest to bloom is the soft lavender Aster frikartii `Monch', which is nearly smothering its neighbours, having grown unrestrainedly in the wet summer.
It starts to unfurl its hard, knotted buds in late July and is followed by at least a dozen other varieties including the compact A. thomsonii `Nanus' and the tall A. turbinellus whose wiry, airy stems carry little violet stars. There will be a moody haze of Michaelmas daisies here until at least the end of this month. Tall monkshood, with its sober deep-blue cowls, competes solemnly, while the dark flower heads of the bergamot, Monarda `Blue Stocking' add more rich colour. Not for nothing is this last plant - which carries leggy, squashed-spider inflorescences - called "bee balm", for it is constantly mobbed by buzzing creatures, frantically collecting the last of the year's nectar.
The purple-pervaded autumn borders are Mary's way of taking a good thing and making it more so: "One year I looked out in the garden at this season," she recalls, "and it looked all purple. And what looked so intensely purple was a piece of Thalictrum delavayi, the meadow rue: and I thought, if a thing looks a certain way, well then you go for it."
And go for it she did, adding purple plants in droves: verbenas, lobelias, penstemons, salvias, phloxes, lythrums, and clematis - these last growing both on supports behind the borders and also wandering around amongst the plants. And then she relieved, and emphasised, the sombreness of the scheme with the silver foliage of various artemisias and the white flowers of Chinese chives and late clematis. The whole lot is set off by a smooth green lawn and is presided over by a lichen-encrusted stone figure.
It all looks so simple, so natural and uncontrived, but that's where the invaluable experience of the veteran gardener comes in. Mary Simpson has been gardening for more than 75 years, and along the way she has amassed an encyclopaedic knowledge of the ways and habits of a multitude of plants.
"I'm a complete plant nutter", she says, and explains that she was hooked early on, when approval came from an unexpected source : "I had a garden when I was five or six. I was digging one day - I was burying a dead bird - and found a penny. And I thought God loved gardeners."
In Mary's front garden another colour dominates the scene: bright, bright reds fill the beds that are separated by narrow gravel paths. The dahlias, `Bishop of Llandaff' and `Bednall Beauty' create eye-opening scarlet splotches, as do the repeated blasts from the floribunda rose, `Trumpeter'. And Mahonia `Moseri' puts on its own constant one-man show: its young leaves start off bronzy-red, then turn to a startling Granny Smith apple-green and finally end up dark-green.
The Scottish flame creeper, Tropaeolum speciosum, is a perennial cousin of the nasturtium: it's one of those plants that can be difficult to establish, but once it makes its home in your garden, you've got it forever, like it or not. Here it rambles down from the boskage behind and swarms through the beds, its long-spurred crimson flowers popping up everywhere.
Diary Date: Saturday, October 11th, from 2.30 p.m. to 4.30 p.m.: the Royal Horticultural Society of Ireland holds a major plant sale at Taney Parish Centre, Taney Road, Dundrum, Co Dublin. Nonmembers: £1.