Mark Driver has been through a lot: difficult childhood, drug and alcohol addiction, failed first marriage, stressful single parenthood, and, at age 46, a heart attack that nearly killed him.

For all he's been through, life is that much sweeter now.

Driver is 57, clean and sober for 20 years, happily married to his second wife, Mary Lou, for 18. He's worked through his childhood pain, and son Zack, 25, is doing great, as is Driver's heart.

It's healthy, in so many ways, as never before.

All of which helps explain why most days at 6:30 a.m. you'll find this slight, blue-eyed "country boy from Memphis" puttering around in his Phoenixville, Pa., garden, counting his blessings one plant — and one day — at a time.

There, he finds transformative pleasure in simple things:

The first blush of lime-green and purple jack-in-the-pulpit. Seven-inch buds on his yellow angel's trumpet. A stand of sea holly crawling with ladybugs. A birch tree's rustle on a breezy day.

"To me," Driver says, "this garden is therapy. Peace. Work. But work is good. I love to work."

And work in the garden he does, from March to November and sometimes beyond, tending to a million tasks, welcoming friends and fellow gardeners, and introducing kids of every age to the "train country farm" he's created in the center of the garden. Who doesn't smile to see a pint-sized steam locomotive rattling down the track, through the tunnel and under the cable car, past the pigs in a mud pit, the dwarf evergreens and hollies?

"From the time I was 9 years old," Driver says, "the urge and desire to know about plants was like the urge to eat ice cream. I think I was born this way."

It began with a cactus in elementary school, then took a detour halfway through high school, when he discovered drugs and alcohol.

Discovery turned to addiction after high school, during a two-year hitch in the Navy, and to drug dealing after his discharge. "I was smoking pot like cigarettes. It was the thing that had me by the throat," Driver recalls.

His is now — and, with luck, will continue to be — a happy tale, so the lost years, while not forgotten, are not the sum of Driver's narrative. Along with Mary Lou, his good health and strong Christian faith, they help make him the grateful gardener he is.

Doesn't hurt that he has great plants, more than 200 perennials, most inherited from a friend who died six years ago. He was her part-time gardener, and Driver says she taught him that "perennials have more design and texture to them, though not necessarily color, unless you have a variety."

He also learned that plants have both botanical and common names, sometimes more than one of each. That plants in the garden should be labeled (Driver writes their names on yard-sale spoons and sticks them in the ground). And that each plant has particular requirements for light, water and food.

He lines the beds with white birch logs, which stand out against the eight yards of triple-shredded hardwood mulch he spreads around every year. No hard-liner, Driver has natives like queen-of-the-prairie and pink milkweed alongside nonnative lilies and hardy orchids.

And you'll never find this gardener sitting at a desk designing flower beds. Driver's style is "to be as natural as possible." Plants go where there's room, where they "look like nature," and if you see a few weeds, chill.

"I like people to see this as a working garden," he says.

Driver has four rain barrels and a sizable collection of bird houses, feeders and baths. He combines organic (earthworms) and nonorganic (Miracle-Gro) fertilizers, and he's thinking about making his own compost.

He's a self-educated gardener, a house painter by trade. After a herniated disk in his neck ended that career, Driver worked garden-related jobs at two big-box stores and a nursery. Now, he delivers medications for a pharmaceutical company.

He met Mary Lou, a medical assistant, at a church lu'au, and the third time he saw her, he gave her three roses. "I said, 'Oh, this is the guy,' " she recalls. Adds Driver, "We knew it when we looked at each other."

All these years later, Driver gives his wife fresh flowers from the garden every single day.

Driver loves to share his garden with visitors: the children next door, the Lower Merion Camera Club, the Garden Club of Hanover, Longwood Gardens students.

He says, "Plants don't play mind games. Plants aren't cruel. Plants don't kill each other or commit crimes."