HARRISBURG -- When Michele Ridge moved here in 1994 with her husband, Tom Ridge, she immediately went outside to look at the governor's residence's garden -- but didn't get much of a view.

The garden sloped off to the iron fence, beyond which was an alley and a parking area, recalled Mrs. Ridge, an avid gardener.

"You went out there to enjoy the rose garden, and basically you were just looking at a parking lot."

That, plus a flood in 1996 that destroyed many of the residence's plantings, prompted her to launch a public-private partnership to redesign the garden that today, after a 13-year bipartisan effort, is reaping praise from proponents of sustainable gardening practices nationally.

There's a new organic herb and vegetable garden planted by the Rendell administration in May. There's "Penn's Woods," a shady enclave of native plants from woodlands and meadows put in by Mrs. Ridge and her husband -- who also loves gardening, she said.

"I was very aware of the damage that invasive plants have done to Pennsylvania gardens," she said, "and here was a chance to showcase on a very small scale the plants and shrubs that are indigenous to this region."

Other improvements have been made in recent years. A new "smart" drip irrigation system delivers water only to the roots to prevent evaporation and waste, while a weather monitoring station prevents it from running in wet weather.

With 15,000 people -- many of them students -- touring the 3.5-acre site each year, Mrs. Ridge, a former teacher, was eager for the governor's gardens to serve as a teaching tool about the environment.

"They would tour inside of the public areas of the house and then they would go out onto the grounds, and I knew we were missing an opportunity for education," she said, noting the mansion's location on the Susquehanna River, with its rich diversity of Pennsylvania flora and fauna.

Actually, an increasing number of governors and mayors around the country are jumping on the "green" bandwagon, spurred by the Obamas and their planting of a vegetable garden at the White House. The Pennsylvania governor's residence, however, is way ahead of most other states when it comes to sustainable practices, says Susan Harris, founder of greenthegrounds.org, which has been urging the White House and governors' and mayors' offices in all 50 states to transform their gardens into models of environmentally sensitive stewardship.

"A vegetable garden is a good beginning, but sustainable gardening is much more than that," says Ms. Harris, a Takoma Park, Md.-based gardening coach who writes for the popular blog gardenrant.com.

"Going green means lessening a reliance on lawns, a halt to the use of pesticides and other chemicals, water conservation and plantings that are drought- and disease-resistant."

That's already mostly happening in Harrisburg, she said in a recent entry on Garden Rant: "Forget old-style, formal landscaping for the governor's grounds in Harrisburg, PA; they're way cooler than that," she wrote, noting they now let the lawn go dormant during periods of drought.

"Brown grass in this high-visibility, official site? Wow, maybe there's hope yet for changing our crazy American expectations for a perfect, always green lawn, water conservation be damned."

On a recent beautiful July day, a horticultural advisory committee of landscape designers, arborists, plant pathologists, turf professionals and state employees who maintain the property were strolling the grounds in Harrisburg, eyeing every blade of grass, every rose, every tree, looking for problems.

A Shasta viburnum had grown too big -- did it need to be cut back yet? A "hole" had opened up in the shade canopy of a star magnolia -- did that mean any problems? A row of Kwanzan cherry trees had grown so large they were shading out the Bonica roses, which had grown leggy and were blooming sparsely. Should they be moved to a sunnier spot close by? (Answers: No, no and yes.)

The governor's mansion, an imposing brick structure built in 1968, has always had a garden, but it wasn't until the late 1990s that fundraising began for a major redesign and renovation, Mrs. Ridge said in a recent phone interview.

Ultimately, a master plan was drawn up that included four separate garden areas: There's the Jane Shafer Rose Garden, named after the wife of former Gov. Ray Shafer; Penn's Woods, a native plant garden; the terraced West Lawn, which is used for large groups and receptions; and the Susquehanna Garden, a private space for the governor's family, sheltered by a yew hedge.

The horticultural advisory committee voted on each plant selected, said Dennis Rydberg, a horticulturist who oversaw the renovations for the state Department of General Services. In Penn's Woods, there are drought- and disease-resistant plants native to Pennsylvania such as trillium, ferns, hollies, heuchera.

"They have to be found in at least one of the 67 counties, or else they don't make the cut," he said, and if they don't thrive in the heavy clay soil, they're removed."

In the formal rose garden, the view of the parking lot has vanished, replaced by two graceful brick pavilions with a pergola linking them where, each spring, 'New Dawn' climbing roses explode into pale pink blooms. And while the original hybrid teas have been retained -- 'Peace' and 'Sonia,' among others -- no-spray roses such as 'Knock Out' and 'Carefree' were added, along with durable, colorful perennials and companion plants -- Nepata 'Blue Wonder' and Salvia 'May Knight.'

Under Gov. Ed Rendell, the garden continues to expand and evolve but with a firm commitment to environmental sustainability, said Mr. Rydberg, who is directing the residence's transition to LEED certification, noting that energy usage has been cut, both in the house and in the garden, while recycling has increased. Wildlife flourishes, too -- a pair of duck eggs nestled in one patch of liriope.

In May, a vegetable garden was planted behind the brick pavilions' wall on the sunny south side of the residence, 120 feet long and 6 feet wide, using mushroom manure from a local firm and organic plants donated through the Pennsylvania Landscape and Nursery Association and the state Department of Agriculture.

Designed by Gloria Day of PrettyDirtyLadies.com, a Berks County garden design firm, the garden has thrived in this summer's abundant rainfall, with heirloom tomatoes trained up a bamboo trellis with sisal twine. Peppers, zucchini, squash, cabbage, carrots, broccoli and other vegetables were planted, along with a variety of herbs and flowers, at the direction of the residence's chef, with any extra food donated to the local food bank.

Two large compost bins sit nearby, and attention is also paid to runoff, with more than half of the rainwater retained on the site. The irrigation system is programmed for 20 different zones and not only stops watering when it's raining but also when rain is in the forecast.

While there are more garden beds per square foot than lawns, it's unlikely the governor's residence will ever fully embrace the no-lawn philosophy espoused by environmental advocates, but soil is constantly tested to determine if fertilizer is needed. While chemicals are kept to a minimum, a pre-emergent synthetic herbicide is applied in early spring.

The governor's garden is changing and evolving, as gardens do, Mr. Rydberg said. Since Mr. Rendell took office, a long walkway near the house has been planted with taller, more shrub-like plants -- Itea, or Virginia sweetspire, known for its glorious fall color, and 'China Girl' holly.

"The Rendells love the garden," he said, noting that their son was married there. "They use it a lot. They enjoy getting outside with their dogs."

Perhaps the garden's most emblematic feature isn't a plant at all -- the Seward Johnson sculpture visitors see when exiting the house onto the West Lawn. "Down to Earth" is a life-sized statue of a woman in a kerchief and jeans, gardening on her hands and knees.

The statue, which is on loan from the Berman Museum of Art at Ursinus College, has special meaning for the woman who helped make the governor's garden what it is today.

"I like it because it's whimsical in a house that's so serious," said Mrs. Ridge. She also likes it "because that's what I did during the first few years. I was down on the ground with my garden tools.

"Then I realized I couldn't do it all myself, that we needed a more sustained effort to enhance the grounds of the residence."

The result, 15 years later, is a model of gardening sustainability that goes well beyond a simple vegetable plot and, who knows, may one day be found at all 50 governors' residences.