Other first ladies - Ginny Thornburgh and Michele Ridge come to mind - were similarly inclined or at least took an interest in the gardens surrounding the 32-room Georgian-style mansion, which dates to 1968 and occupies three acres along Front Street across from the Susquehanna River.
But Corbett, by all accounts, is unusually knowledgeable and enthusiastic about the landscape, as well as appreciative of the therapeutic respite it provides from her newly public existence.
"When I really want to chill, I come here in the morning and sit on this bench with a cup of coffee and the morning papers," she says while strolling through Penn's Woods, a cool, cavelike woodland garden layered with lady's slipper, Jack in the pulpit, and other Pennsylvania native trees, shrubs, and wildflowers whose every name she knows.
Actually, Corbett seems much keener on active involvement than passive appreciation. She really digs the stuff non-gardeners hate - the sweaty, tedious work of weeding, pruning, and clipping spent flowers, which she sometimes does right before public events or after the gates close behind the day's last obligation.
"I'll put on the rattiest sweatshirt and shorts you can imagine and rubber boots or sneakers and gloves, grab my little rolling cart and tools, and head out," she says.
To Penn's Woods, maybe, or the Susquehanna Garden, a private area for the governor's family, or the West Lawn, a classy venue for special events and receptions.
Often, you'll find her in everyone's favorite spot - the formal Rose Garden, just off the State Dining Room. Here, you can imagine how a glass of wine, a beautiful sunset, and that sweet "Mister Lincoln" rose fragrance might conspire to disarm a governor's most obstreperous foe.
Imagine all you like. Corbett won't go there.
"It's a really tough job" is all she says of her husband's position. "No matter what you do, half the people are going to disagree with you, and if you do the opposite, the other half won't like it."
She shrugs, adding, "This place really is a retreat."
After the Corbetts' arrival last year, the retreat added some new features: for the chef, a vegetable and herb garden; for the new first lady, who's fascinated by bees, two beehives (with fancy copper roofs) and a cut-flower garden for those arresting table arrangements.
Corbett, a native of tiny Pine Grove, Schuylkill County, learned about gardening from her mother and a Pennsylvania Dutch grandmother who was married to a coal miner.
"My grandparents lived in a modest home in the country, and I remember she had the most beautiful gloxinia growing in coffee cans. They looked like big African violets," says Corbett, whose mother, at 92, walks with a cane and has balance problems but still weeds and putters around in her garden for five hours at a stretch.
"She's frustrated. She used to spend the whole day," says Corbett, one of four gardening sisters.
The first year she and Tom Corbett were married - it'll be 40 years on Dec. 16 - they planted a vegetable garden. She went for herbs; he grew - gulp - 72 tomato plants. "The next year, he planted only about a dozen," Corbett says mischievously, careful not to make too much fun of that inaugural tomato avalanche.
The couple have a son, Tom 3d, 35, who works for AT&T in New York, and a daughter, Kate Corbett Gibson, 32, a lawyer with the state Attorney General's Office in Philadelphia. Kate's 9-month-old son, Liam, is the Corbetts' first grandchild.
For 36 years, Susan and Tom Corbett have lived in his family's pre-Civil War farmhouse on an acre in North Hills, just outside Pittsburgh. She misses that garden immensely - the old lilacs, the pink-and-red climbing roses of long-forgotten provenance, even the requisite "mystery plants" every family inherits.
By the time Corbett and her husband move back, she expects four - or eight - years of neglect will have changed the landscape considerably. "The deer are loving my lilies," she says.
Talk about changed landscapes. The gubernatorial gardens had to be replanted from scratch after being wiped out in 1972 by Hurricane Agnes. The waves crested at five feet inside the house, which was accessible only by boat.
This past September, Tropical Storm Lee forced the Corbetts to evacuate briefly. The West Lawn had to be resodded, and although the rose leaves turned black and fell off, they came back just fine this year.
Even in the best of times, this is not a given. The soil here is a nightmarish heavy clay with poor drainage.
But over the years, the gardens' caretakers - in 2012, that's three staffers, supplemented by local master gardener volunteers - have learned: Don't fight the natural conditions. Work with them.
As Corbett tells the staff, "Pick what grows here." There's no attempt to massively overhaul the soil. What manages to grow is a keeper.
What grows in the these gardens has changed dramatically since 1992, when horticulturist Dennis J. Rydberg started working at the Governor's Residence. Back then, he recalls, the color palette was salmon and more salmon - to match the bricks of the house - and lots of tulips and geraniums.
"It was very nice but very dated and not very diverse, but, you know, that was the style when the building went in, and it matched the Georgian architecture nicely," he says.
After the Ridges arrived in 1994, Michele spearheaded what turned into a 15-year public-private effort to raise money and redesign the gardens to incorporate more plant variety, four-season displays, and sustainable practices.
"If you have nothing in a rose garden but roses, it's pretty boring, but also, if you get a rose disease, it gets everything," says Paul W. Meyer, director of the Morris Arboretum in Chestnut Hill and one of many advisers on matters involving the governor's house and gardens.
Today, the rose garden is planted with traditional and modern hybrid teas, as well as more easygoing varieties that continuously bloom and resist disease. There are lots of perennials and shrubs, and more birds, bees, and beneficial insects than ever before.
"Going forward," Meyer says, "like any gardener, we'll be adding and tweaking and refining our gardens, and Mrs. Corbett has taken a great interest in that. We hope she'll put her stamp of personality on the garden."
No worries there. Corbett has already shown herself to be pleasantly assertive on matters horticultural, seeking out cool plants at Stauffer's and Ashcombe's nurseries around Harrisburg and shopping for ideas at Philadelphia's many public gardens and the Philadelphia International Flower Show.
She has gone to the show for years but never, as was the case in March right after she became first lady, surrounded by a scrum of VIPs and media, marketing, and security personnel.
"We can't go out unless someone lets us out and goes with us," Corbett says.
No wonder she gravitates to the gardens whenever she can, often with the family's two Airedale terrier puppies. They're rambunctious siblings whom schoolchildren around the state voted to name Harry for Harrisburg and Penny for Pennsylvania.
Corbett liberates them from behind a gate, and they tumble and streak across the West Lawn, oblivious to the fact that grown-up manners are expected in this space.
Corbett repeatedly yells, "Harry! Penny! Come here," but they're on critter patrol, scratching and digging and burying their noses inside the dense, grassy ground cover.
Which Corbett, of course, takes time to identify. "Liriope," she says.
Pennsylvania first lady Susan Corbett describes the popular Rose Garden at the Governor's Residence in Harrisburg at
Contact Virginia A. Smith at 215-854-5720 or firstname.lastname@example.org.