Marjorie Unger Bayersdorfer, 75, a social worker and award-winning gardener who championed the use of native plants to beautify and preserve the environment, died of ovarian cancer last Sunday at the Hill at Whitemarsh, a retirement community in Lafayette Hill.

Before daughter-in-law Cyane Gresham, a gardening expert, and a conference at Millersville University opened Mrs. Bayersdorfer's eyes to native plants, her gardening was a beloved pasttime that merely created a lovely landscape.

But learning about beautiful varieties that also preserve the environment and provide a habitat for insects and wildlife transformed her into an evangelist for native plants and turned her garden into more than a pretty picture. "She believed very strongly that we are destroying the environment and we should do all we can to protect it," said her husband, H. David Bayersdorfer.

Mrs. Bayersdorfer served as director of the native-plants program at the Pennypack Ecological Restoration Trust in Huntingdon Valley, which administers 720 acres in the Pennypack Creek watershed.

She led a corps of volunteers who propagated native plants for sale at the trust's headquarters. She spoke frequently to gardening clubs and was the driving force behind the creation of an award-winning butterfly garden near the trust's visitors center. She also helped spearhead the development of High School Park, a native-plant park in Cheltenham.

Mrs. Bayersdorfer was born in Petersburg, Va., and moved to Elkins Park when she married. She had met her future husband at a wedding.

She was a full-time homemaker raising three children until she enrolled at Temple University at age 39. She earned a bachelor's degree in psychology and later a master's degree in social services from Bryn Mawr College. She worked briefly for Jewish Family and Children's Service of Greater Philadelphia and then went into private practice.

Mrs. Bayersdorfer began transforming her garden to one rife with native plants in the early 1990s after attending her first Conference on Native Plants in the Landscape at Millersville.

She and her husband pulled up the carpetlike pachysandra and planted ferns, tiarella, and shrubs including azaleas. Immediately, the bumblebees, butterflies and birds began to visit; the soil became rich with nutrients and absorbed storm water more easily. Motorists stopped to admire the view.

"My bathroom window is up there," Mrs. Bayersdorfer said, pointing to a second-floor room during a 2003 interview with The Inquirer. "Every morning I look out and say, 'Ah, how did I get blessed with this?' "

In addition to her husband of 58 years, Mrs. Bayersdorfer is survived by sons Alan and Mitchell, one granddaughter, two brothers, and a sister. Son Robert died in 1970.

A memorial service is scheduled for 2 p.m. April 26 at the butterfly garden at Pennypack Ecological Restoration Trust, 2955 Edge Hill Rd., Huntingdon Valley, Pa. 19006.

Memorial donations may be sent to the trust.