The month of May has long been associated with the Blessed Virgin Mary. As St. Paul VI noted in his 1965 encyclical Mense Maio, May "is the month during which Christians, in their churches and their homes, offer the Virgin Mother more fervent and loving acts of homage and veneration; and it is the month in which a greater abundance of God's merciful gifts comes down to us from our Mother's throne."

The abundance of flowers this month recalls the fruitfulness of Mary's "Fiat" to God's will in her life. While many flowers are associated with Mary in art, devotion, and folklore, two appear most often: The lily and the rose. 

Lilies were taken to symbolize Mary's perpetual virginity and freedom from original sin.  Artists depicting the Annunciation very often included a pot of white lilies in the scene, or showed St. Gabriel presenting a white lily to Mary in token of her purity. A lily species has the popular name "Madonna lily" because it was so often shown in artistic works with Mary. There are other flowers called "lily" which are not really lilies but are closely associated with Mary -- for example, the "Assumption Lily" (a type of hosta) that blooms about the Feast of the Assumption in mid-August and the "Sword Lily" (Iris) that symbolizes Mary's Seven Sorrows. The fleur-de-lys is said to symbolize Mary because it resembles both the Madonna lily and the iris. 

Roses are another Marian floral symbol, as explained by John S. Stokes in his 1996 book Mary's Garden: "In the medieval period, the rose was adopted as the flower symbol of the Virgin Birth, as expressed in Dante's phrase, 'The Rose wherein the Divine Word was made flesh,' and depicted in the central rose windows of the great gothic cathedrals -- from which came the Christmas carol, 'Lo, How a Rose 'ere Blooming.'" In the Litany of Loreto, one of Mary's titles is "Mystical Rose." St. John Henry Newman said that Mary is called a rose because it is the most beautiful of flowers and she is the most beautiful of women. Mary is sometimes referred to as the "rose without thorns," the rose representing the beauty of holiness without the thorns of original sin. The word "Rosary" -- the most popular Marian devotion -- means "a crown of roses," or spiritual bouquet presented to Mary.