Roses can be a sign of prayers answered, or the presence of a particular saint, and many other things, however, roses are NOT associated with the Crown of Thorns.
I’ll give you some interesting links, but I would caution you: don’t read too much into it without the expressed advice of your confessor or spiritual director.
ewtn.com/v/experts/showmessage.asp?number=453239
saltandlighttv.org/blogfeed/getpost.php?id=38052&language=en
St. Therese of Lisieux said she would shower down roses from heaven
Our Lady of Guadalupe gave Juan Diego a tilma full of roses in winter as proof for his Bishop
and many other miracles of roses in history.
Also this:
ROSE: In Catholic symbolism, the red rose is a symbol of Martyrdom, while the white rose is a symbol of purity since the earliest years of Cthe Church. St. Ambrose relates how the rose came to have thorns. Before it became one of the flowers of the earth, the rose grew in Paradise without thorns. Only after the fall of man did the rose take on its thorns to remind man of the sins he had committed and his fall from grace; whereas its fragrance and beauty continued to remind him of the splendor of Paradise. It is probably in reference to this that the Virgin Mary is called a ‘rose without thorns,’ because she was exempt from Original Sin.
In Renaissance art, a garland of roses is often an allusion to the Rosary of the Blessed Virgin.
The Glastonbury [also called the Christmas Rose] Rose is both the symbol for the Mother of God and for the Infant King, Who didst come to earth to be crowned with thorns as part of His Passion and Death whereby He renders atonement to God the Father for the sins of men, in order to win their redemption. The Glastonbury rose is an exquisite flower, without comparison, but it also bears the sharpest of thorns, like those that were plaited into Our Lord’s Passion crown. Moreover, just as the Epiphany, which means manifestation, can be said to point to the Savior, so does this special Rose, which blooms just before dawn on January 6, the Feast of Epiphany. Nothing is coincidental with God.
Before the Glastonbury rose came to be, Christians drew Mystical roses like a pointed star and crafted beautiful stain glass windows, depicting the Rose. They still do. Some quilters work entire quilts with the theme and there is a Mystical Rose quilt template.