Draw the stem, and a circle. On top of the circle, draw a kind of oval.
Connect the top "oval" to the circle. Draw two lines coming out of the circle. Add two leaves.
Draw the petals. Draw a small spiral in the middle of the top oval.
We now add spines to the stem, and to the leaves. We draw the nerve in the leaves, and we erase the circle. We add hairs on the bottom of the flower, and we make the spiral more rose-like. And done!
Evolution of our rose:
If you want, you can colour the rose to make it look better!