Backlighting has the ability to silhouette, illuminate through translucence, create a halo or corona, dissolve edges to heighten volume, magnify size, focus and elevate attention, suggest advancing or retreating motion and, dramatically exaggerate the subject. Photography like painting exploits these principles. Backlighting can be a technique to thwart cliché. The more clichéd the subject the more cause for the artist to develop a more unusual and potent presentation. Flowers can quickly become clichéd images. Their potential as subjects can easily be lost because, the artist/photographer simply considers them as a colorful topic or idea rather than a singular moment subject to enhancement through a novel point of view. Even simple laziness often subverts photography and painting. Here are some examples. In example 1. 
Notice a lighter red corona running its jagged course along the perimeter of the flowers. If these flowers were shot with light falling across the photographers shoulder rather than their present back-lit (contre-jour) condition we would see only one value of red. They would appear uniform in color, flatter in form and with no range of contrast. All qualities given by backlighting. To achieve this back-lit enhancement I dropped to the ground and aimed the camera up into the sunlight. The plants only stand 18 to 22 inches off the ground. Even the leaves have a better range of color and value, reaching from dark green to bright lime. Notice that most of the upper background appears in dark shadow which propels the rear illuminated flowers closer to the viewer. Find a background that is shadowed when illuminating your subject from behind. In example 2.
Backlighting can be further enhanced by the design of the subject. Here the design is triangular ( see the superimposed red diagram).
The backlighting reveals deep purples in the shadow and pastel-white violets in the sunlight. I have red-dotted the three principle flowers creating this triangle. The backlighting helps separate the green buds from the shadows of the flowers because, it generates a thin perimeter of light yellow around the bud (see red-circled bud). Again, I crouched low to find this light. In example 3. 
Here the subject offers foreshortening effects which enhance the perception of volume and also, offer multiple color identities for same subject. Because the sun’s light falls from both above and behind the elements of this subject we can see the back-lit fronds as glowing slivers of orange while the toplit fronds extending forward to the viewer have a bright blue or violet quality. The forward cascade of foreshortened fronds are in the diagrammed image. I have demonstrated this effect in painting in a previous blog. 
In example 4.
The light again falls from above and behind. I am only inches from my subject to make it appear large and simplify the design. Backlighting pushes through the sheer central petal and, amplifies the spot of yellow with its veins of pink radiating up as if they were a light source all themselves. The composition is an inverted triangle as seen in the diagram. 
In the final example the light falls from above onto the sides of leaves. With a shadowed background the leaves appear to hover, isolated magically in space. The leaves are shot at an inclined angle to the ground plane to give the impression of a slipping lateral movement. The stem supporting the illuminted white flower runs in counterpoint to the motion of the leaves. Example 5. 

Randi davis
Really enjoyed reading and hearing your perspective on what could be a simple subject. Great job!!
Maggie Black
I always learn so much from you David. It is my goal to one day be able to enroll in one of your workshops. You are not only a wonderful artist but a great teacher. I always “get” what you’re teaching and that isn’t true with all teachers. This particular lesson helped me with a picture I am beginning today which has backlighting. Example 4 with that glowing yellow center is stunning. Thank you so much for sharing your wealth of knowledge.
Fredric Neuwirth
I am glad that you have resumed your insiteful & thoughtful blog.. So much to learn about seeing! It would be interesting to see the backlighting in a painting; not of flowers.
Finally have gotten around to reading ” The Wiorld in Six Songs ” by Levitin. This weeks NY Times Book Review has a worth while review of Johnny Depp & the impact of music & his keen interest in Woodie Githrie.