Here we see a 14th Century painting of the Madonna of the Rose. The rose is often associated with the Mother archetype. Carl Jung points out that the mother archetype “can be attached to … various vessels such as the baptismal font, or to vessel-shaped flowers like the rose.” (9i, para. 157) In the Western tradition we see the rose associated with the Virgin Mary. Cardinal Newman (1801 – 1890) said:
“She is the Queen of spiritual flowers; and therefore, is called the Rose, for the rose is called of all flowers the most beautiful. But, moreover, she is the Mystical or Hidden Rose, for mystical means hidden.”
The divine mother archetype is related to the hidden. She represents the mystical gnosis, and the rose is a symbol of such gnosis.
Reference: Carl G. Jung, The Archetypes and the Collective Unconscious – Collected Works volume 9i (originally published 1934–1954)