Here are the elements:
1 - a flower
2 - a straight line
3 - complementary colors
I don't think there will be much debate over the first element: a flower. A flower is a flower. Nor should the second element, a straight line, be very contentious. The important thing is the straight line be a prominent element of the photograph. We don't care if it's a horizon line, a straight edge rule, the angle of a wall, or the side of a vase. It just needs to be a pronounced straight line.
The final element is complementary colors. These are colors which are directly opposite from one another on the color wheel, NOT simply colors which go well together. We don't care what colors you use, we don't care about the source of the colors, all we care is that the colors are complementary. We sort of assume one of the colors will be the flower, but that's entirely up to you.
We recognize that there are at least two similar but distinct color wheels. We don't care which color wheel you use to determine the complementary colors. If you have questions about complementary colors, you may want to look first at the discussion in wikipedia.