Polly Hill, the pioneering horticulturist whose internationally acclaimed work raising trees and shrubs from seed began 50 years ago on a former sheep farm in North Tisbury, died Wednesday morning at Cokesbury Village, her home in Hockessin, Del. She had turned 100 in January.

An amateur scientist, botanist and plant geneticist, Polly Hill’s work rocked the horticulture world by shattering the notion of zonal gardening, which is based on the premise that certain plants grow only in certain climates. Today the 70-acre former North Tisbury farm that was her laboratory for more than 40 years is the Polly Hill Arboretum, where nearly 2,000 plants and trees are displayed around large meadows punctuated by rambling 18th century stone walls. The collection includes camellias and towering magnolias which no one knew could grow north of the Mason-Dixon line, a nationally recognized collection of Stewartia trees, and hardy hollies, conifers, viburnums and rhododendrons. Over the years Polly introduced more than 100 species, including 22 North Tisbury azaleas — low-growing, late blooming, hardy plants, all named after her children and grandchildren.

The arboretum, which is open to the public, was permanently preserved in 1997 through a generous gift from the late Dr. David Smith of West Tisbury.

“Here is a woman who at 50 years old . . . . began as an experimenter. She is a researcher and she is a risk-taker. If you want to start over again, Polly is the model,” Dr. Smith told the Gazette in an interview in 1997.

“I hope that some of the foreign plants I have had so much pleasure in growing will take hold in the Island soil and become permanent Vineyarders,” Polly wrote in a 1964 article in Horticulture Magazine.

And indeed they did.

Mary Louisa Butcher was born on Jan. 30, 1907, the daughter of Howard Butcher Jr. and Margaret Keen Butcher of Ardmore, Pa. Known as Polly from childhood, she attended the Phoebe Anna Thorne Open-Air School for Girls of Bryn Mawr College, where the classrooms had roofs but no walls. In the winter the girls bundled up with mittens and sleeping bags. She later graduated from the Agnes Irwin School and Vassar College, where she majored in music and briefly considered a career as a composer. After college she worked for a year in Tokyo, Japan, teaching English and field hockey at a girls’ college. She also studied traditional flower arrangement.

In 1931 a friend introduced her to Dr. Julian Hill, an organic chemist and a member of the team that had discovered nylon at DuPont. His sojourn in Japan had begun as a child when his father was buying railroad ties for the Atchison, Topeka and Santa Fe Railroad. Julian and Polly married in 1932. They settled in Wilmington, Del., the headquarters for DuPont, and had three children.

When her children were growing up Polly planted a World War II victory garden at a community garden site a mile away from her home. She commuted to her garden on a bicycle, her youngest child stationed behind her in a wooden box fastened onto the bike.

After the war she studied botany and horticulture at the University of Delaware and at Longwood, a well-known public garden near Wilmington.

In 1957 she and her husband took ownership of Barnard’s Inn Farm, formerly the Smith sheep farm in North Tisbury, where Polly’s family had summered since 1927. Polly began to develop 20 acres of fields into a garden specializing in trees and shrubs. Her mission was to evaluate the best plants and trees to grow on the Vineyard — all from seed. Her husband’s work took him around the world and Polly traveled with him, collecting seeds that she later used in her experiments. She grew most of her specimens in a small outdoor nursery and gave them no attention during the cold season. Seedlings that survived passed the first test as plants suitable for the Vineyard. She studied her trees and shrubs closely for desirable characteristics, selecting the best and later introducing many to the horticulture world.

She never sold her seeds, but instead gave them away, sending them in the mail to horticulturists around the globe.

Later she created what became known famously as her playpen, a planting area the length of a football field surrounded by a deer fence ten feet high. The garden contains her signature North Tisbury azaleas, many of them grown from Japanese seeds.

Known for riding around her property in a bright yellow golf cart, Polly was smart and task-oriented and brooked no nonsense, especially when it came to professional standards in the horticultural world. In a 1998 interview in the Gazette on the eve of the opening of the arboretum, she aimed pointed remarks at professionals who visit gardens with an eye toward taking home a few cuttings.

“People should know that it’s now public, but it doesn’t mean that people own the plants. The plants belong to the arboretum and they have rules. If you are interested in cuttings or pieces, please put it in writing,” she said.

Writing things down was another one of her trademarks. She kept detailed and meticulous records over the years, chronicling her successes — and also her failures. She had enormous patience for her specimens. One of her rare plants, a rhododendron grown from wild seed that she had gathered on the Delmarva Peninsula, took 29 years to bloom.

“What we are seeing in its most native form, she has done genetic engineering. She has stressed the genetic system to render its full potential,” Dr. Smith told the Gazette in the 1997 interview.

This was Polly’s motto for watering: “Every day for a week, every week for a month and every month for a year. Then they’re on their own.”

Her methods were widely chronicled in an array of respected horticulture journals over a period of decades.

Her husband Dr. Julian W. Hill died in 1996 at the age of 91.

A year later Dr. Smith and Polly formed an unusual conservation alliance that allowed the arboretum to be protected permanently as a nonprofit center for horticultural research and education. For the next seven years Polly continued to live in residential quarters on the property known as the cow barn in the summer months, still maintaining daily records of blooming and fruiting plants. She retired at the age of 97.

Dr. Smith, a distinguished scientist in his own right who helped develop a vaccine against childhood meningitis in the 1980s, died in 1999.

This winter while Polly celebrated her 100th birthday at her home in Delaware, at her arboretum on the Vineyard a greenhouse — something she never had — was unveiled in her name. “Polly always had a real optimism for the future. When you decide to plant a tree, you have to be optimistic. You are looking to give something to a future generation,” said arboretum executive director Tim Boland.

At the time of her death this week, daffodils, magnolias, cherry trees and winter hazel were all in bloom at the arboretum, surrounded by greening fields.

She is survived by her daughter Louisa Spottswood Coughlin of Philadelphia, Pa., two sons, Joseph J. Hill of Radnor, Pa., and Jefferson B. Hill of Washington, D.C.; two grandsons, three granddaughters and three great-grandchildren; a brother, Keen Butcher of Philadelphia, and many descendants of her other three brothers and sisters who predeceased her.

A memorial celebration of her life will be held in Cokesbury Village in Hockessin, Del. at 10 a.m. on Saturday, May 5. Another celebration will be held on the Vineyard in the summer at a date to be announced.

Donations may be made to the Polly Hill Arboretum Endowment Fund, P.O. Box 561, West Tisbury, MA 02575.