The black background came from my black camera bag. My son, Tim, had to stand in such a way as to shadow the bag without shadowing the plant.
Still, the bag was slightly visible in the shot...this is where a good photo editing program like Photoshop, Corel PhotoPaint, etc. comes into play. I can adjust the brightness levels to knock the near-black shades to black and bring up the bright levels to near-white. Here was the original, undoctored shot from my camera:
As you can see, there was another spike intruding into the corner, a visible camera bag (complete with spot of red-orange lint), and flowers that were only medium-bright...I digitally fixed that to get a better-looking photo.
---Prem