Born Dec. 4, 1927, in El Dorado, Kansas, died Apr. 20, 2026, Huntsville, Alabama, after a short stay in Regency Health and Rehab, following a fall in December.

Mary Lou lived throughout most of her early years in Lubbock, Texas, where she graduated from Lubbock High School and from Texas Tech with a degree in Music Education. She became the first girl ever in the junior high school band there. It was at Texas Tech that she met her husband, Robert McNabb, who was also a musician in the marching band. They were married when Robert was home on leave after his Army basic training, before he was sent to Berlin, Germany, for 18 months, and they were married for over 72 years. When he returned, they moved to Austin, Texas, for him to finish his engineering degree, and their daughter, Ann, was born. Robert and Mary Lou moved around the country 22 times for assignments with IBM, with their son, Bob, being born in Galveston, Texas, and their daughter, Carol, being born in Seattle. They settled in Huntsville in 1962. Mary Lou played her flute in orchestras wherever they lived, including for many years in the Huntsville Symphony, and taught flute and piano lessons. She became involved in gardening and flower arranging, for which she won numerous ribbons, and served as a national master flower show judge for many years.

They built a house on their country property in Brownsboro in 1972, but were transferred by IBM to Endicott, New York, only a year later, where they lived until Robert’s retirement. While in New York, Mary Lou attended gardening classes and became a certified Master Gardener. When they returned to Huntsville in 1980, they started planting blueberry bushes on their country property, eventually running a pick-your-own blueberry farm, which was enjoyed by multiple generations of customers for 32 years. Mary Lou is widely considered to be the instigator and “mother” of the Alabama Master Gardener program, based on the program she attended in New York. She was gratified that thousands of people have now taken these classes across the state and have thus become better gardeners. In addition, she and her husband were early supporters of the Huntsville Botanical Garden, for which they raised substantial funds. Its circular fountain is named in their honor. She was a 43-year member of the Herb Society of America, a co-founding member of the Huntsville Herb Society in 1984, and of the Master Gardeners of North Alabama in 1988. She wrote the horticulture column for the Huntsville Botanical Garden newsletter for six years, gave frequent garden club lectures, and was interviewed by local television and the newspaper several times. After decades of keeping meticulous gardening journals, she wrote and published a gardening book in 2017 geared toward gardening in north Alabama, Sow it, Grow it, Know it, which quickly sold out, with all proceeds donated to the Master Gardeners of North Alabama.

Mary Lou had a deep love of nature and traveled with her family to many of the national parks while their children were growing up. She and her husband enjoyed trips to England and France to see various gardens. They studied Spanish together for several years in continuing education classes and enjoyed numerous tours throughout Mexico, where they could practice speaking it. Other activities she enjoyed were square dancing with her husband, sewing, and swimming.

In her later years, Mary Lou continued to live independently on her farm, where she enjoyed gardening and was a voracious reader. She was grateful to her friends and neighbors who assisted her in so many ways after Robert’s passing in 2019, particularly Ronnie Hamilton, Debbie Holmes, Margaret Certain, and Dr. Noel Estopinal, as well as to her daughter, Ann. She was a longtime member of First United Methodist Church in Huntsville and the Faith Sunday School class there, which meant a great deal to her.

She was predeceased by her parents, James Richard Stewart and Dorice Bozeman Stewart, her brother, James Stewart, her sister, Sue Young, and her husband, Robert. She is survived by her three children, Ann Swanson of Huntsville, Bob McNabb (Lois) of Sherwood Forest, California, and Carol McNabb Goodwin (Sydney) of Harlingen, Texas, as well as two grandchildren, Jennifer McNabb of Sherman Oaks, California, and Michael McNabb of Mountain View, California.

A Celebration of Life will be held at First United Methodist Church, Huntsville, on Sunday, June 14, beginning with a visitation at 3:00 and a service at 4:00.

In lieu of flowers, donations may be made to the Huntsville Hospital Foundation, First United Methodist Church of Huntsville New Futures fund, the University of Texas Rio Grande Valley McNabb Endowed Woodwind Scholarship fund, or a charity of your choice.