They've climbed high into mountains in China; they've knocked on doors of houses along rural roads in Georgia; they've slammed on brakes after spotting a variegated branch on a shrub that was otherwise all green.

These are just a sampling of the ways three renowned plantsmen, Don Jacobs, Mike Dirr and Ted Stephens, have made important discoveries that have ended up in our gardens or will be there in the near future.

Martha Tate / Special (ENLARGE)

'Morning Calm,' a peach-colored trumpet vine, was introduced by the late J.C. Raulston.

Martha Tate / Special (ENLARGE)

Lantana 'Chapel Hill Yellow' is Martha's plant pick.

RELATED LINKS: • Photos: See the plants Explorers brave Asian wilderness to gather seeds  Landscaping book a helpful design reference  Buy plants like they're honey-baked hams  Uncertain times call for thrifty gardening  Bold, beautiful Dahlias add a cheerful mix to any garden  • Get more Home & Garden news

"It's a lot of word of mouth, hearing about a plant someone has, or finding a sport and then starting to propagate it," said Ted Stephens, a self-described "plant nut" and co-owner of Nurseries Caroliniana, a wholesale and retail nursery in North Augusta, S.C. Stephens travels to Japan "once or twice a year" in search of the new, interesting or rare. He is responsible for saving and promoting plants in the area where his family has lived for more than 250 years. An example of the latter is a historic Chinese wisteria that still grows at Augusta National Golf Club. This vine, known as Wisteria sinensis "Augusta's Pride," was introduced from Belgium by an Augusta nursery in the early 1800s. The plant is significant because, unlike the common Chinese wisteria, it blooms at an early age.

While Stephens has made many of his own introductions, he is just as enthusiastic about promoting other good garden plants, like the highly fragrant tea olive, Osmanthus fragrans "Fudingzhu," and Campsis grandiflora "Morning Calm," a peach-colored trumpet vine introduced by the late J.C. Raulston at North Carolina State University in Raleigh.

Retired University of Georgia professor Mike Dirr is famous for his "Manual of Woody Landscape Plants" and two newer books on hydrangeas and viburnums. He's also made scores of important introductions, including the repeat-blooming Hydrangea macrophylla "Endless Summer," sometimes dubbed as the "great blue hope" for northern gardeners. From 2004 until the end of 2007, more than 7 million of these hydrangeas were sold across the world, with millions more arriving in nurseries this year.

"There's a lot of pure, unadulterated luck in this business," says Dirr, who spotted what became "Endless Summer" at Bailey Nurseries in St. Paul, Minn.

"I saw this hydrangea blooming on Sept. 11, 1998, in a section that was about to be bulldozed," recalled Dirr. "It had both new and mature blooms on it and some buds that hadn't opened. It had been there for probably 15 years. One of the workers at Bailey had found it in a neighbor's yard in St. Paul. I asked if I could have cuttings."

A similar near-miss occurred with a crape myrtle called "White Chocolate," which has bronze leaves, white flowers and a compact habit.

"We were after dwarf plants, and this one grew too large," said Dirr. "It was in a group about to be thrown away when we realized it had this unbelievable contrast of foliage and flowers."

Dirr said that selecting plants takes time and that there are disappointments.

"You can have a promising plant, but it never becomes stable," he said. "Sometimes we'll watch a plant for 10 years before we think it should be mass marketed."

At age 88, Don Jacobs is still planting seeds and making crosses in pursuit of good garden plants. While he discovered his well-known ground cover, Lysimachia "Eco Dark Satin," on Mt. Emei in China, his newest introduction is a cross he made in his Decatur garden. Loropetalum "Eco Perfumed Diva" is a small shrub with arching branches, burgundy leaves and rich pink flowers that are highly fragrant.

"I was trying to breed the fragrance of the old-fashioned white loropetalum into the new burgundy forms," says Jacobs. "This plant went far beyond what I had anticipated."

Jacobs has made many choice plants available to gardeners over the decades. At present, he is excited about Chamaecyparis pisifera "Eco Blue Fern," a dwarf conifer that holds its sky-blue foliage all year, and Lapeirousia "Brite Eyes,'" a bulb resembling a dwarf gladiolus that's just coming into bloom.

Botanical name: Lantana camara "Chapel Hill Yellow"

About the plant: This hybrid between the cold hardy "Miss Huff" and the tender "New Gold" appeared as a chance seedling in the garden of Susy Dirr, Mike Dirr's beloved daughter who died earlier this year from cystic fibrosis. Yellow flowers appear from spring until fall. Perennial to Zone 7. A portion of the royalties from "Chapel Hill Yellow" will go to the Sweet Melissa Fund for lung transplant patients and families at the University of North Carolina.

Use in the garden: An excellent container plant, or good for cheerful color in the garden.

Planting and care: Plant in well-drained soil in full sun.

Source: Land Arts, Inc., 809 Broad St., Monroe GA 30656, 770-267-4500, www.landarts.com.