The arboretum association at St. Mary's College of Maryland was created in the fall of 2010. St. Mary's College of Maryland is a strikingly beautiful campus positioned on the banks of the St. Mary's River, near the point at which the river joins with the Potomac. As such, they are a tidewater campus with a fragile ecosystem that is responsible not only to 2,000 undergraduate students annually as the state of Maryland's sole public honors college, but also to an entire watershed area, with corresponding populations of people, plants, animals and fish. Long before they adopted the title of Arboretum they were fully engaged in protecting the trees, plants, soil and watershed.

St. Mary's College of Maryland has 361 acres; 53% of the campus exhibits an established tree canopy. An additional 5% is aspirational canopy (afforested area, with young whips being grown out in meadows and buffer spaces), and recently they converted 22 acres of lawn area to meadows and treed spaces. Last year they created a healing garden, installing simple benching and over 300 native plants in a treed space dedicated to counseling services support; this school year students plan an Arbor week initiative to create an on-campus apple grove where they will plant disease-resistant and non-herbicide specimen trees. Another student plans a green roof renovation project exhibiting current industry practice for such a space. They firmly believe in the old adage "you cannot change the world until you know and improve your community."