I did choose the composition so that there was a single purple leaf that provided a point of interest. I probably should have done a little staging to make that leaf just a bit more prominent.
Here are a couple more floral shots with the same thought in mind.
One technical note: If the entire field is part of the subject of the image, then depth of field can be important. For these shots, not only did I look for arrays that were largely in one plane, but I used a very narrow aperture, in these cases f/40, to achieve greater depth of field.
OK, so the following shot of a single mum doesn't quite fit this wall-to-wall description.
Not only is there a single flower, but I have left a little blank background on the edges. But it is a nice shot, and I wanted to leave the background to better define the flower's margin. Besides, I could have cropped the image down.
Here is another image of a single flower that also leaves some "empty" background. However, this seems more in line with the wall-to-wall thesis of the earlier shots. I think that is because in this case I have cropped down the blossom's tips.
This creates the perception of a possibly much larger bloom, almost simulating an explosion. I tried some shots that included the full blossoms but didn't think they were as effective.
Here's a leaf shot that fits the same pattern.
I converted this shot to a black & white to emphasize the lines created by the wavy margins of the leaves. Again, I chose to have the leaves fill the image, in this case to create an abstract quality. For the record, this was shot at f/3.5, leaving the forward edges of only two of the leaves in good focus. That seemed to work for my purposes.
Finally, here is another leaf shot, my favorite of this post.
Again, this was a wall-to-wall shot (at least as cropped) and happened to have very good resolution. I was also able to keep the background dark.