It's an enclave of churned-up mud on the north side of Steeles Avenue in Brampton, in a sea of frenzied subdivision development. I have a picture in my mind's eye of this place, the farm Keith Squires purchased back in 1954 when he was 26 years old. This is nothing like that image - but I search for the spot as I drive past.

He's described it to me, this memory from over half a century ago.

"If you're coming from Number 10 Highway on Steeles Avenue, like I say, you go over the hill and straighten out and there's a Canadian Pacific railroad there. The Canadian Pacific Railroad is the whole west fence line of that property. Soon as you cross over the railroad, you drop down into the river valley – the Credit River valley. Now there's a bridge there, but when I moved there, the bridge wasn't there. When I moved there, there was no Steeles Avenue, it was Baseline."

This was Churchville then, and here is the Churchville Road, and the railway line running north alongside it, and here is the Credit River which overflowed its banks in 1954, Hurricane Hazel hitting the year Keith moved here. Now, I've driven past the spot, swept along by an unrelenting flow of traffic, three lanes of traffic west, and three lanes going east. It takes time to figure out a way to turn and come back. This must be it, because here is the sign proclaiming that the church of St. Eugene de Mazenod is to be built here. All around, tight rows of houses, just finished or almost complete, each peak-roofed module clad in pastel aluminum or pale brick, crowded up against its neighbour but still detached, proudly independent, if only by a few feet..

To the east, massive willows and oaks along the banks of the Credit that I fancy may have been here before Keith arrived and are here years after he moved on, driven away by financial disaster. But all other signs of the plant business he built here are gone, erased from the land. The Country Squires Garden has been re-established some 50 kilometres to the west, on the height of the Niagara Escarpment. There, an aerial photograph of the Brampton home farm hangs on the wall, the house centred in a sea of green, a woodlot over to a corner, no other buildings in sight beyond the ones Keith built himself.

"They took the soil for the bridge over the river out of my back area there, out of the valley at the back. Just fill, just ordinary soil that they put out for the bridge. The contractor was from down around St. Thomas. He went into bankruptcy, a train hit the flatbed of his truck. That happened way down London way. And I couldn't get paid."

"Ah. you've had a lifetime of this," his wife Carolyn teases.

Keith laughs. "Yeah, he went into bankruptcy, you couldn't get any money out of him because the train hit the flatbed. They figured out it was his fault - he shouldn't have gone out on that track in front of the train."

We're in Campbellville, sitting at a small table in the L-shaped kitchen. The south facing wall is all window and covered with plastic to keep the heat in. You can't see out but still, the sun streams in. The green patterned linoleum is well worn, the walls are covered with brown wood paneling and a fridge and freezer take up all of the central wall. The sink and counter run along the wall next to a small washroom. Round the corner is Keith's office – just books and paper on the desk, along with one of those old black phones with a cradle for the receiver, and a rotary dial. Carolyn's is next door; she has a small computer that was thrown out by a hospital some years ago and is not hooked up to the internet because that, Keith will not allow – for fear it would allow his competitors to steal valuable commercial information. There are plants everywhere, huge plants that are years old, like the tree-sized Kalanchoe from Madagascar and new plants, like the orange tree Carolyn started from a pit.

This is one of the buildings from Brampton, first used as to store bulbs in, with living quarters crammed in for Keith's young family. "This was originally my bedroom," he says, standing in his office, "that was the kids' bedroom and that was the kitchen. We had three children in this building." Then he built a proper home, and he got out of Gladiolus and into perennials. "And I had no use for the building any more, I but kept it anyway," he says. "It was a nice building to have." As is often the case with people who keep stuff, years later, he found a use for it.

I can't remember why I first decided to make the trip to Campbellville to visit the Country Squires Garden. As a gardener, I was always looking for something new, not this year's colour or the hottest hybrid, but a better understanding of what it is to make a garden. The garden centre chains and grocery store summer sales had lost their appeal and I found myself drawn to specialists. My job took me all over Ontario and the magic of a sign bearing the word 'perennial' never failed to lure me off the highway. What joy! to follow the trail to some sleepy former agricultural centre and find a little hole-in-the-wall nursery, tended by some fellow enthusiast with a passion for the unusual.

But it wouldn't have been a roadside sign that took me to Keith Squires, because there isn't one. Certainly not one of those expensive blue signs purchased from the company that has the contract for Ontario highway 'signage.' And when you turn off Highway 401 onto the Guelph Line, there's no sign there, either, not even at Derry Road where you hang a right at the gas station and carry on up the hill. There is a sign on the property which is large and painted in bright red on a yellow background but somehow I always seem to sail past and so have to go a little way down the road and turn back.

Just writing down the directions conjures up the distinctive nasal tones of horticulturalist Art Drysdale, who used to host a phone-in garden show on a Toronto radio station. This was in the nineties, on Saturday mornings. It was an exciting time for gardeners. I remember a glow of pride one chilly late-winter Saturday when the radio was warning of problems on Highway 401 because of the number of gardeners taking the Airport Road exit to attend the first-ever Canada Blooms show. 'Those are my people,' I thought, as the announcer puzzled over the weirdness of it. Keith was a regular on Drysdale's show.

They were a couple of crusty old contrarians, inveighing against environmentalists and contemptuous of fads. A detail that caught my attention: Keith was a fourth-generation nurseryman. In Canada, that's unusual. So it was that one brisk day in April, 1999, I pulled in to the parking lot at the Country Squires Garden, assigned by the Toronto Star to write a piece for the gardening page. I fell in love immediately - with a low-growing white potentilla, its four-petalled face so pure in the bright sunshine, growing in a scree bed by the entrance. Little did I know how much I was going to learn about gardening in scree or gravel, even though I am privileged to garden in rich silty soil just south of the Canadian Shield.

Step inside the garden centre and you realize right away you're not in any ordinary plant-purveying outlet. It's open and airy and shaded, with serried lines of pots on waist-high wooden benches running the length and breadth of the structure. The floor is earth. Large hand-lettered signs indicate what plants are where – shade to the right, sunlovers to the left. Small hand-lettered signs are suspended by wooden clothes pegs from wires above the benches. Keith and Carolyn come forward, courteous and authoritative. We fall into easy conversation. Keith explains that he has specialized in perennials since the 1950s.

Annuals? Pshaw! "I've seen gorgeous gardens of petunias and geraniums, with maybe a bit of cleome shooting out from behind. But after three weeks, you're going to come out your door and not look at your garden. You've seen it, you've seen that petunia in bloom. So you walk to the car and drive away. It's boring. You don't see it anymore."

But a perennial garden? It's a continuing parade, from the short-lived delphinium to the 300-year-old peony, he rhapsodizes. "You come out in the morning and, all of a sudden, something's in bloom. And a day later, it's something else." His eyes light up. "It's interesting, it's ongoing, it's why you got into gardening in the first place."

Keith's mantra – that a perennial garden should need neither watering, fertilizing nor weeding – must have struck a chord with my readers. When the story appears, the switchboard is deluged with calls from people trying to find him. The story says the nursery's in Campbellville, but the street address and phone number are not included. And the Country Squires Garden can't be found in the phone book.

Typically, Keith figures the kerfuffle is my fault. "You really messed up there," he chortles indulgently over the phone, admitting to having been swamped by customers in the aftermath of publication. At least one of them leaves his garden centre in high dudgeon and calls me to demand an explanation. "I don't know why you would write about anyone so rude," the caller says. "I've never been treated like that. He refused to do business. He told me to leave." Keith allows that he had had a difference of opinion with a customer, although he does not divulge any details.

I guess the customer should have read my story more carefully. In it, I pointed out that Keith will not stand for his plants being killed off by some ignoramus. "We do not tolerate people losing plants. All hell breaks loose around here when one of our plants has been killed. We want to know what the heck happened, where did you grow it?" Improper location is the culprit in 90 per cent of losses - a shade plant baking in the sun, or a drought-lover languishing with wet feet. On occasion, Keith will quiz a customer on whether he has the right requirements. "He'll say, 'No, but I love this plant.' And I'll say 'No, I won't sell it to you.' "

In subsequent years, I make sure to detour down to Campbellville whenever I'm passing on Highway 401, and stock up on plants as budget permits – Keith doesn't try to compete with the chains, and he never has a sale, so his plants are not inexpensive. On the other hand, they are good value. Keith takes no shortcuts. The work of propagation and testing is painstaking and the methods, I come to learn, hearken back to a pre-industrial age. Some years later, I take a year to follow him through the seasons. This book is the result, a story in which plants play a starring role and a crusty octogenarian is the canny impresario. It's a story for gardeners.

Chapter 1: Seeds, Seeds, Seeds