Flowers of all hue, and without thorn the rose.

Every rose has its thorn

At last he rose, and twitched his mantle blue; / Tomorrow to fresh woods, and pastures new.

A thorn defends the rose, harming only those who would steal the blossom.

If you want to say it with flowers, a single rose says: "I'm cheap

But he that dares not grasp the thorn Should never crave the rose.