The reference of the Rose of Sharon is to the Shulamite woman, the lover of Solomon as penned in Song of Solomon 2.
Back in the OT, the plains of Sharon were fertile and filled with flowers and the rose was considered a very valuable flower. As for Jesus being called the Rose of Sharon, it is most likely because of He is the lover of our very souls. He alone is BEAUTIFUL and His value is immeasurable!
It's awesome when we consider the various and sundry ways God went about preaching the Gospel in the Old Testament?
Here are some other attributes of the Rose of Sharon
THE ROSE OF SHARON IS THE FLOWER OF THE FIELD
ROSES OF THE FIELD - Not planted by men (God planted the roses of Sharon)
ROSES OF THE FIELD - Subject to be trodden by men (the world trod the Saviour underfoot)
ROSES ARE UNIVERSAL - Roses grow in just about every climate in all types of soil. The application can be made to Christianity as it also grows around the world.
ROSES OF THE FIELD WERE FREE - The poorest could have them without money and without price - conversely the rich could pay no more for they were free - even as Salvation. PRAISE THE LORD!
Credit goes to whom it is due
from the book The Names of Christ by Dr. James Modlish