A Mary Garden is a devotional garden planned around a shrine to the Virgin Mary. This style of devotional garden is most closely associated with Catholic tradition, although people of other Christian denominations may also construct Mary Gardens. The concept of the Mary Garden is closely linked with the medieval hortus conclusus, or “closed garden.” Mary Gardens can be found in private homes and around Catholic churches, community halls, and other gathering places.

The practice of making Mary Gardens appears to date back to the medieval period, when monks and nuns constructed closed garden shrines to Our Lady, as Catholics sometimes call the Virgin Mary. By tradition, a Mary Garden is in an enclosed area, referencing her purity, although when enclosed space is limited, it is certainly possible to put a Mary Garden in an open area, and sometimes boundaries by low fences or walls are used to create a partially enclosed feel.

In a Mary Garden, people plant a variety of flowers, trees, and shrubs associated with the Virgin Mary. Zinnias, snapdragons, Sweet Alyssum, cornflowers, Impatiens, larkspur, marigolds, forget-me-nots, poppies, morning glories, petunias, and sweet scabious are all associated with the Virgin Mary in Catholic folklore. Other plants one might see in a Mary Garden include laurel trees, mayweed, maidenhair ferns, strawberries, ladyslipper orchids, lily of the valley, trefoil, columbine, ribbongrass, peonies, foxgloves, bachelor's buttons, Amaryllis, begonias, bellflowers, bluets, buttercups, violets, irises, and roses.

A statue of the Virgin is common in a Mary Garden. Some Mary Gardens have a Madonna and Child, while others simply show the Virgin Mary alone, and other religious figures may be included. Commonly, a bench or patio is included so that people can sit in contemplation in the Mary Garden, and gardeners may use a water feature to muffle outside noise, or a birdbath to encourage birds to visit. There may be a space to light candles while saying prayers.

The layout of a Mary Garden can vary considerably. Some people set a Mary Garden up in the shape of a cross, while others make patterns with raised beds. Since some Catholics attach specific meanings to various flowers, the Mary Garden may also be laid out with a winding path which allows people to contemplate various aspects of the Virgin Mary. Overall, the design is meant to be peaceful and pleasant, with the goal of promoting deep thought and providing a space for prayers and contemplation on religious issues.