Northview, Carey's 4.5-acre garden, is a popular tour destination. She has started a blog about it called BeforeYouGarden.com, and said she hopes it will answer practical questions and inspire gardeners to see the connections between gardening and history and the arts.
"I'm an educator by training, a teacher, so I want it be educational and fun, lighthearted, but also help people learn how to garden," said Carey, a Temple Ambler alumna who grew up in England as the daughter of a botanist.
Vicki Lewis-McGarvey, vice provost for University College, which includes the Ambler Arboretum, said Carey would be missed.
"She has helped make the Ambler Arboretum a true destination for anyone interested in education, history, and gardens," Lewis-McGarvey said in a statement.
Carey cites as her proudest accomplishments raising money to improve old gardens or restore new ones on the 187-acre campus on Meetinghouse Road, including the Albright Winter Garden, Ballard Healing Garden, and Colibraro Conifer Garden.
The Wetland Garden was recently completed.
Founded as the Pennsylvania School of Horticulture for Women, Temple Ambler, a school of horticulture and landscape architecture, celebrated its centennial in 2011. A new visitor center honoring the Woman's National Farm and Garden Association, a century old in 2014, will open soon.
"I feel like the time is right," Carey said of her decision. "I just need to do it."
Besides writing, Carey says she will continue to welcome visitors to Northview, do speaking engagements, and guest lecture at the Arboretum School at the Barnes in Merion.
There was no word Wednesday on how or when her successor would be chosen.